September 29, 2025
Updated: February 14, 2026
An unbiased, research-driven comparison of leading UK penetration testing providers to help CISOs and procurement teams shortlist with confidence.
Mohammed Khalil
Choosing the right penetration testing partner is mission critical in 2026’s high stakes cyber landscape. Nearly half of UK businesses reported experiencing a cyber attack or breach in the past year. High profile incidents underscore the risk a single ransomware breach at a UK retailer was estimated to cost around £300 million in lost profits. At the same time, attackers are leveraging emerging techniques like deepfake phishing and infostealer driven password harvesting to steal massive volumes of credentials, fueling an epidemic of stealthy account takeovers and identity based attacks. This raises the bar for security testing as firms must defend against AI enhanced threats and subtle intrusion methods. Meanwhile, organizations face relentless compliance pressure to demonstrate due diligence; regulators now demand rigorous testing and proof of remediation rather than check the box audits.
The UK penetration testing market has matured to meet these challenges, featuring both homegrown specialists and global consultancies with UK based teams. Security budgets have risen accordingly 92% of organizations increased cybersecurity spending last year, with 85% boosting investment in pentesting specifically. In fact, the global pentesting market is projected to grow from $2.15 billion in 2026 to $5.0 billion by 2030, underscoring how critical these services have become. With threats growing and standards tightening, companies can’t afford a trial and error approach to choosing a provider.
This independent, research driven ranking aims to help UK organizations navigate the options and find a partner that fits their needs. We’ve evaluated leading penetration testing firms from boutique experts to large consultancies against transparent criteria detailed below to ensure a fair, procurement friendly comparison. The result is a list of the top penetration testing companies in the UK for 2026, each with proven expertise. Whether you run a small tech startup or a large regulated enterprise, this guide will help you compare vendors, understand their strengths and limitations, and ultimately make a confident buying decision.
Our evaluation methodology is grounded in E E A T principles Experience, Expertise, Authoritativeness, Trustworthiness and a commitment to transparency. Each provider was assessed across multiple factors:
UK Ranking Emphasis: In line with the above, UK centric qualities were prioritized. UK headquartered specialists form the core of our rankings. Global consultancies are included only if they have a deep UK pentesting practice e.g. a UK office with dedicated testers and extensive UK client work. CREST accreditation remains a strong quality indicator especially for government and finance engagements but it was not treated as an absolute must if equivalent expertise was evident. Ultimately, every company on this list met our bar for technical excellence and proven UK delivery. We believe this approach keeps the rankings fair, relevant, and procurement friendly for UK organizations’ needs.
Selecting a penetration testing firm is a high stakes decision. A common mistake is treating pentesting as a commodity purchase in reality, provider capabilities vary widely. Below are key considerations to guide your choice, along with red flags to watch for and what truly matters versus marketing claims:
By focusing on these criteria and watching for the red flags, you can cut through marketing noise and choose a penetration testing partner that will genuinely help strengthen your security posture. The next section applies this lens to the leading providers in the UK market for 2026.
Now, let’s dive into the top penetration testing providers operating in the UK and see how they stack up. Each company listing includes key facts headquarters, founding year, size, etc., an explanation of why they stand out, notable strengths, potential limitations, and ideal best for use cases. The list is organized with UK based specialists first, followed by international players with a strong UK presence, reflecting the local emphasis of our rankings.
Why They Stand Out: DeepStrike is a next generation provider that combines elite human expertise with a modern SaaS delivery model. Founded by recognized security experts including former authors of the Web Application Hacker’s Handbook, DeepStrike has a strong pedigree in manual penetration testing. Every engagement is heavily manual and creative the firm’s philosophy is to simulate real attackers using custom exploits and multi-step attack chains, rather than relying on off the shelf scanners. What truly differentiates DeepStrike is its fully managed PTaaS platform: clients get a cloud portal to track findings in real time, integrate with tools like Slack/Jira for updates, and manage remediation workflows. This hybrid approach expert led testing + a continuous platform gives clients the best of both worlds deep, one off tests when needed and ongoing visibility between tests.
Key Strengths:
Potential Limitations: Being a newer player founded 2016, DeepStrike is still growing its brand recognition and global footprint. They are in the process of obtaining CREST accreditation and expect to be certified in 2026, but as of early 2026 they are not yet a CREST member so extremely compliance conscious clients might require an already CREST certified vendor for certain engagements. Additionally, while the company’s boutique size allows for great personal attention, very large enterprises needing hundreds of tests per year or extensive on site presence might find DeepStrike’s team relative to big firms stretched if not planned well in advance. They also don’t offer a huge menu of ancillary services like managed SOC or large scale audit/compliance consulting DeepStrike focuses on penetration testing and offensive security. However, for the vast majority of mid-sized and even large UK organizations, DeepStrike’s capabilities are more than sufficient and often more cost flexible and responsive than what larger audit firms provide.
Best For: Organizations that want a high impact penetration testing program with both depth and ongoing coverage. DeepStrike is ideal for tech driven companies including scale ups and cloud first enterprises that value creative, manual testing and continuous engagement through a platform. It’s the top choice if you seek a true security partner who can adapt to your development pace for example, DevOps teams releasing frequently, or any business that wants to integrate pentesting into a continuous security practice rather than a one and done yearly audit.
Why They Stand Out: NCC Group is a powerhouse in the cybersecurity consulting world and a heavyweight in the UK pentesting scene. With a 20+ year history, NCC has built an unparalleled knowledge base and resource pool including dedicated research teams that spend thousands of hours annually discovering new vulnerabilities and attack techniques. Their penetration testing services cover virtually every niche from wireless and hardware testing to social engineering, meaning they can handle very complex, large scope engagements with ease. Crucially, NCC Group carries significant credibility in regulated sectors. They are a CREST member and one of the few firms with NCSC CHECK status to perform government work. Enterprises often choose NCC for high assurance needs because of its proven methodologies and the comfort of working with an established, publicly listed company. In many ways, NCC is synonymous with comprehensive security provider if you need a one stop partner with global reach, they are always in the conversation.
Key Strengths:
Potential Limitations: As a large firm, NCC Group’s services typically come at a premium price point and often with more formal processes. Smaller organizations might find the sales and onboarding process a bit too enterprise oriented or slow compared to leaner firms. NCC may also rotate team members on lengthy projects, which can introduce learning curves though they manage knowledge transfer well. Another consideration is that highly creative outside the box findings the kind of quirky, cutting edge hacks a boutique researcher might land could be missed if an engagement sticks too rigidly to standardized test plans. NCC’s emphasis on process is a strength but can also mean engagements feel by the book; they do encourage creativity, but the experience might vary by team. Additionally, because NCC offers so many services, clients should ensure their immediate needs penetration testing get adequate focus and aren’t overshadowed by pitches for other services NCC tends not to aggressively upsell, but the breadth can be both a blessing and a complexity if multiple teams get involved.
Best For: Organizations that want a top tier, established partner with global capabilities. NCC Group is especially suitable for large enterprises, financial institutions, or government bodies that require the assurance of a big name firm with extensive resources. If your company operates internationally and needs consistent testing quality across regions, NCC is a strong candidate. It’s also a great choice when you have a mix of needs say you need pentesting now, but might also require incident response or security strategy consulting later; NCC can cover it all, providing continuity. In short, choose NCC Group if you value breadth, experience, and a proven track record they are the veteran firm that likely has seen it all, which can be very reassuring when navigating modern cyber risks.
Why They Stand Out: Pen Test Partners often known as PTP has a reputation as a go to boutique for deep technical expertise. Unlike many firms that diversify into managed services or compliance, PTP focuses almost solely on penetration testing and related offensive work. This specialization means their consultants are true experts; many are conference speakers, DEF CON presenters, or contributors to well known security research. PTP is particularly known for tackling unusual and challenging assignments essentially, if it has a computer in it, they can pentest it. Over the years, their team has famously hacked maritime vessel systems, tested commercial aircraft cybersecurity, compromised IoT gadgets and smart appliances, and more. As a result, PTP is one of the few firms of its size capable of high end engagements like CBEST Bank of England’s regulated bank simulations. Despite being an independent ~100 person company, they punch well above their weight in skill and have gained global recognition through public research and thought leadership.
Key Strengths:
Potential Limitations: Pen Test Partners’ focus on complex, bespoke testing means they may be relatively expensive for simpler needs. They tend to take on projects that require significant expertise; a small business looking for a quick, basic pentest might find PTP’s offering more than necessary and their pricing aligned to their specialist skills. Additionally, their capacity is limited to about 100 consultants while that is large for a boutique, extremely large scale rollouts e.g. hundreds of apps or sites simultaneously could be challenging to schedule all at once. PTP also does not provide many ancillary services no managed SOC or extensive GRC consulting they stick to what they do best. So if you prefer a single provider for all security services, PTP’s narrow focus might mean you use them alongside other firms. Finally, because they thrive on challenging work, they might not be the cheapest option for routine compliance driven testing though they certainly can do it. In short, they’re optimized for depth, not breadth or volume.
Best For: Organizations that need top tier technical depth in penetration testing. PTP is best for mid size to large companies who value quality over quantity for instance, a bank needing a no compromise red team engagement, or a manufacturer seeking to secure unusual connected technology. It’s an excellent fit for critical infrastructure providers and any business facing sophisticated threats and possibly regulators that demand an experienced, independent testing partner. If you have a challenging environment or a novel technology to be tested, Pen Test Partners should be high on your shortlist.
Why They Stand Out: Nettitude is distinguished by its dual DNA strong technical pentesting capabilities combined with a compliance/audit mindset. Now operating under the LRQA banner Lloyd’s Register’s assurance division, Nettitude leverages its parent company’s legacy in standards and certifications. This means when Nettitude performs a penetration test, they keep an eye on how the findings relate to frameworks like ISO 27001, SOC 2, or sector specific regulations. They often provide one stop services: a company can get their required audits PCI DSS scans, ISO 27001 readiness assessments, etc. and their technical security testing done through a single provider. Nettitude is a CREST member and also an approved NCSC CHECK service provider, so they are cleared for UK government work. Their team carries not only technical certifications OSCP, GIAC GPEN, etc. but also qualifications like PCI QSA and ISO 27001 Lead Auditor a blend that supports both technical depth and paperwork rigor. Clients in finance and critical infrastructure often choose Nettitude for big red team exercises mandated by regulators such as Bank of England’s CBEST, because Nettitude can deliver the adversarial testing while ensuring all the compliance reporting boxes are checked. They produce very polished, executive friendly reports that map vulnerabilities to risk categories and to compliance controls. In terms of innovation, Nettitude invests in developing tools and techniques they describe themselves as research led, but always with an eye toward reliability and standards. Their approach is methodical and professional, making them a trusted advisor in boardrooms and audit committees.
Key Strengths:
Potential Limitations: Because Nettitude heavily emphasizes compliance and structured methodology, some tech startups or fast moving companies might find their approach a bit conservative or slower compared to a pure hacking boutique. Their engagements tend to be very formal which is great for quality control, but maybe less agile for rapid testing needs. Pricing can also reflect their dual value you’re somewhat paying for both the security expertise and the compliance assurance. If an organization only wants a bare bones pentest with no interest in the compliance context, Nettitude might not be the lowest cost option, as their added value could be superfluous in that scenario. Additionally, as part of a larger corporation LRQA, there might be a bit more bureaucracy in contracting and scheduling compared to a small independent shop. Finally, while Nettitude does cutting edge security work, they don’t market themselves as flashy or cool so organizations looking for a sexy, cutting edge image like some Silicon Valley firms do might underestimate them. In reality, they’re very capable, but their branding leans toward the traditional/professional side.
Best For: Medium to large enterprises in regulated industries finance, insurance, healthcare, government, maritime, etc. that need penetration testing with a side of compliance assurance. Nettitude is best for organizations that value both technical findings and having the paperwork in order. If your pentesting program is driven by audit requirements or you know your executives will ask how this maps to our compliance checklist, Nettitude is an ideal partner. They’re also excellent for any company facing a must not fail security test like a central bank mandated red team or a critical infrastructure assessment because of their proven, methodical approach. In summary, choose Nettitude if you want a capable technical team that will also ensure the process and results satisfy the strictest oversight.
Why They Stand Out: Bulletproof is a newer entrant relative to some giants, but it has quickly carved out a niche as a one stop security provider for SMB and mid sized clients. They pair traditional pentesting services with a strong emphasis on compliance needs for instance, they often bundle penetration tests as part of broader packages for things like PCI DSS audits, ISO 27001 certification support, or UK Cyber Essentials. Bulletproof is CREST approved and ISO 27001 certified themselves, signaling credibility to prospective customers. Uniquely, they operate a UK based Security Operations Centre and can offer 24/7 threat monitoring and managed SIEM as an extension of their testing engagements. This means clients can engage them not just for one off tests, but also for ongoing security operations if needed. Bulletproof’s approach is described as very accessible and customer friendly; they offer fixed price testing bundles ideal for smaller companies e.g. a simple external + web app test for a set fee, with quick scheduling and turnaround. Their reports strive to distill findings into business terms, avoiding heavy jargon, which is appreciated by IT managers who may not be security specialists. Many startups and mid size firms choose Bulletproof because they get both technical assurance e.g. a CREST certified pentest and guidance on improving policies and compliance, all from one provider. The company’s leadership including OSCP certified experts often shares insights via webinars and blogs, further building trust with the community.
Key Strengths:
Potential Limitations: Being focused on SMB and mid market, Bulletproof might not have the same depth of specialty skills for extremely complex projects that some larger or niche firms do. For example, ultra sophisticated red team exercises involving nation state level tactics, or testing of very novel technologies like custom cryptographic systems, may be outside their typical scope. Large enterprises with global footprints might find Bulletproof’s geographic reach limited they are primarily UK based though they can service projects remotely around the world to some extent. Also, if an organization only wants a very narrowly scoped, purely technical test with no interest in the compliance or managed service add ons, they might find Bulletproof’s extra offerings unnecessary such clients could opt for a specialist boutique instead. Lastly, as a company oriented to broad cybersecurity services, Bulletproof might not have the singular reputation in the pentest community that some specialist firms do they’re known more generally in the UK mid market but not as much on the global research stage, for instance.
Best For: Small and mid sized organizations in the UK that need professional security testing and compliance support at a reasonable cost. Bulletproof is a great fit for companies that lack internal security teams they can function as an outsourced security partner, handling everything from testing to daily monitoring if required. It’s especially suitable for SaaS startups, online retailers, fintech apps, and any business that needs to meet standards like ISO 27001 or Cyber Essentials while also improving their security posture. For these clients, Bulletproof provides a convenient all in one solution with a friendly touch. Mid-market companies in growth mode who might soon face enterprise level security requirements also benefit from Bulletproof’s blend of testing and advisory to build a solid foundation.
Why They Stand Out: Secarma is renowned in the UK security community for its pure offensive security focus and attacker mindset. The company’s origins date back to a pentesting firm established in 2001, and over the years Secarma has maintained a culture of hardcore ethical hacking. They are the team you call when you really want to be challenged by your pentest. Secarma’s consultants often operate like real threat actors their red team engagements might span multiple months with persistent attack campaigns, custom malware implants, and covert techniques to evade detection. In fact, Secarma has been an early contributor to frameworks like CBEST and GBEST UK’s bank and government red teaming programs, helping shape how advanced simulations are conducted. They also invest in R&D, having developed in house tools for example, an implant called EndView has been mentioned in industry circles. Unlike some firms that do pentesting alongside many other services, Secarma sticks almost exclusively to offensive security, which has honed their skills deeply in this domain.
Key Strengths:
Potential Limitations: As a specialized offensive shop, Secarma may not be the right fit for routine or compliance driven testing of a simple web app their skills and pricing are geared towards more complex scenarios. They are often engaged by organizations that already have a mature security program and now want to push the limits. If you’re new to security testing, Secarma’s style might be overkill, and they might even advise you to get the basics in place first. Additionally, Secarma doesn’t advertise broader services they are not the ones to do your ISO 27001 audit or manage your SOC. So, they work best alongside your internal team or other providers, not as a one stop shop for all security needs. Their availability can also be an issue: truly good red teamers are in high demand, so you may need to schedule well in advance for a major engagement. Finally, because they focus on offense, you should ensure you have the capability to act on their findings. Secarma will give you the brutally honest truth about your weaknesses, but remediation will largely be up to you or other consultants. Organizations need to be prepared for potentially sobering results and ready to allocate effort to improvements otherwise an advanced test could go to waste.
Best For: Organizations that want to be challenged at the highest level of penetration testing. Secarma is best for medium to large enterprises that have gotten past basic security audits and now need to test their resilience against skilled, determined attackers. It’s a top choice for companies with mature security operations banks, government bodies, large healthcare providers, critical infrastructure looking to validate their defenses through realistic red teaming. If your priority is to simulate an advanced cyber attack to see how far an intruder could get and to train your defenders in the process, Secarma is an ideal partner. It’s essentially offense on hard mode, perfect for fortifying organizations that cannot afford a single serious breach.
Why They Stand Out: BAE Systems Applied Intelligence often shortened to BAE AI or now BAE Digital Intelligence is the cybersecurity arm of BAE Systems, one of the world’s largest defense contractors. It brings a defense grade approach to commercial cybersecurity challenges. With roots in Detica a renowned UK defense/intel consultancy, BAE AI has a legacy of working on classified government projects, and the methodologies from that world inform their services to banks, telcos, and others. They are known for handling incredibly complex, large scale security projects: e.g., building secure systems integration for government networks, running security operations centers that analyze nation state threat actors, etc. For penetration testing and red teaming, BAE can deploy elite teams often composed of ex military or intelligence personnel alongside top tier ethical hackers. They tend to simulate sophisticated threat actors, leveraging internal threat intel feeds to inform scenarios. A key differentiator is that BAE pairs cyber technology solutions they have proprietary software for threat detection, analytics, etc. with consulting. So a client might engage BAE to implement a big data security analytics platform and also test their infrastructure. BAE’s global reach is extensive over 4,000 staff in 40+ offices worldwide meaning they can operate wherever the client is, often with local clearance. They also have deep expertise in protecting critical systems like military tech and satellites, which can translate into extreme assurance for critical enterprise systems. While BAE’s services are not cheap and often geared to large projects, the advantage is a one stop powerhouse that can marshal vast resources. Their reports and deliverables carry an authoritative tone that can be useful when presenting to boards or regulators having BAE Systems name on a security assessment often instills confidence that it was done to a high standard.
Key Strengths:
Potential Limitations: For many commercial businesses, BAE Systems AI can be overkill. Their engagement processes, inherited from defense contracting, are very formal and can be slower moving. They tend to focus on very large clients; a mid-sized company might find themselves a smaller fish in BAE’s client roster and possibly not get the same level of attentiveness they would from a smaller provider. The cost is high you’re partly paying for the BAE brand and extensive overhead. Also, because BAE offers so many services, if you only need a quick pentest, the sales and delivery process might feel too cumbersome compared to a specialist firm. In short, BAE is not as agile or cost efficient for straightforward needs. Some tech startups or agile companies might also feel that BAE’s style is too conservative or old school in approach, as they are very process driven. Lastly, BAE’s public presence in the community blog posts, open tools is not as prevalent as some pure security firms they do a lot behind closed doors. So if you are looking to gain public kudos or cutting edge research out of your engagement, that’s not really their model.
Best For: Government agencies, defense contractors, and large enterprises that require the utmost assurance and have the budget to match. Also suitable for big banks or telecom giants that want a provider with equal global stature and the ability to handle projects intersecting with national security. If an organization values having a big name defense expert and possibly needs a combination of software + services, BAE Systems Applied Intelligence is a top contender. Essentially, when the stakes are extremely high and you need a partner who has seen the most advanced cyber warfare techniques, BAE fits the bill.
Why They Stand Out: Kroll is a well known global firm in risk management, and through the acquisition of Redscan in 2021 it significantly bolstered its cybersecurity offerings. Now operating as Redscan a Kroll business, they provide a blend of offensive security expertise and managed security services. This dual capability means Kroll can both identify vulnerabilities and help continuously protect against them. They leverage frontline threat intelligence from their incident response cases and MDR platform to inform their penetration tests. For example, if Kroll’s SOC has been tracking a new ransomware tactic, their pentesters might incorporate that technique in a red team exercise. This integration of real threat data is a differentiator. Kroll/Redscan is CREST accredited for pentesting and their MDR service is well regarded for instance, they have won awards in the MDR space. Transparency and quality reporting are emphasized clients receive detailed reports from pentests and can also get ongoing metrics via the Responder MDR portal. Another reason they stand out is incident response pedigree: Kroll is often called in for major breaches globally, so their security team has a deep understanding of how attackers operate in the wild. They bring that perspective to their testing engagements, focusing on likely attack paths and stealth techniques. For organizations that want a single provider to handle both proactive and reactive security, Kroll is a strong candidate.
Key Strengths:
Potential Limitations: As part of a large global firm, Kroll’s services are not the cheapest their pricing will reflect the enterprise grade quality and breadth. Smaller businesses might find more cost effective local options if they only need a simple pentest and none of the added value Kroll brings. Also, because Kroll does a lot digital forensics, incident response, advisory, MDR, etc., clients seeking a boutique like experience might feel it’s a bit more corporate in engagement. The integration of services is great if you use them, but if you just want a stand alone pentest, you might get some upsell suggestions e.g. offering to overlay an MDR trial. That being said, Kroll isn’t overly pushy compared to some big firms. Another consideration: their pentest team, while skilled, doesn’t have the public rockstar persona of some hacking boutiques if you’re looking for conference famous testers, that’s not Kroll’s style. And if you already have an MDR or SOC provider, you might not fully utilize Kroll’s unique combo; in that case you’d be using them just for testing, which is fine, but part of their differentiator would be moot.
Best For: Mid sized to large organizations that want a well rounded security partner capable of both finding vulnerabilities and defending against them. Kroll is ideal for companies that may not have a large internal security team and could benefit from outsourcing not just testing but also continuous monitoring. Sectors like finance, healthcare, and legal which often deal with frequent threats and strict compliance align well with Kroll’s services they can do CREST certified tests and also handle things like PCI Forensic Investigations or GDPR breaches if needed. Also, any UK business that operates internationally and wants consistent global support will find Kroll’s presence useful. In summary, choose Kroll Redscan if you value the integration of offensive and defensive security under a reputable global brand, and if you want a partner who can stick with you before, during, and after a security incident.
Why They Stand Out: IOActive is a pioneer in the field of hardware and device penetration testing. While they certainly offer conventional pentesting, their claim to fame is breaking things that most other firms don’t even touch cars, satellites, trains, medical devices, industrial robots, you name it. They have a world renowned hardware lab with equipment for chip off analysis, side channel attacks, and other hardware hacking techniques. IOActive’s researchers have repeatedly made headlines for discovering vulnerabilities in everything from pacemakers to automobile CAN bus systems. This research driven approach carries into their client work, meaning if you have a product or environment that’s not just web apps and servers, IOActive has likely tested something similar and possibly built custom exploits for it. That said, they also handle regular enterprise pentests, often bringing a bit of that hacker maker mentality to find novel issues. Their global presence offices across several continents allows them to serve clients locally and tap a diverse pool of talent. For companies building cutting edge tech or wanting a very deep dive into the security of bespoke systems, IOActive is a top choice.
Key Strengths:
Potential Limitations: For standard IT pentesting like a routine corporate web app or internal network test, IOActive can certainly do it, but their pricing might be higher than competitors who specialize in high volume, repetitive testing given IOActive’s focus on research grade work. Thus, organizations with very straightforward needs might not see the cost benefit if they don’t require IOActive’s special skills. Another factor is scheduling: their unique experts are in demand for big research projects and conference talks, so lining up the right team might take lead time you’re not just pulling a consultant off a bench; you might be booking the person who hacked a 787 airplane to test your drone, for example. Additionally, IOActive’s reports can be very detailed and technical especially for hardware findings; some clients may need help interpreting and implementing fixes, as the solutions might involve changes to product design or even manufacturing processes. IOActive is also less about ongoing managed services they come in for a deep assessment, but they’re not typically offering continuous testing programs or SOC monitoring like some others. So, companies looking for a long term managed security partner might still need to supplement with another provider for day to day defense.
Best For: Organizations developing or deploying unconventional or high tech systems think automotive manufacturers, aerospace companies, IoT/robotics device makers, healthcare device companies, or energy firms with SCADA systems. If you have smart devices, embedded systems, or critical infrastructure that needs security testing, IOActive is the premier choice. They are also ideal for financial or tech companies that want a very senior, research oriented team to test their applications at a deeper level perhaps trying exotic attack vectors involving hardware tokens, proprietary algorithms, etc. In summary, choose IOActive when your security assessment needs go beyond the ordinary and into the realm of specialized technical complexity.
Why They Stand Out: Trustwave’s SpiderLabs is an elite team within a larger security organization. They have decades of experience in penetration testing and have discovered numerous high profile vulnerabilities SpiderLabs researchers are known for their work on malware like GoldenSpy, and for contributions to Metasploit, etc.. What makes Trustwave stand out is the combination of a world class threat intelligence and research team with a broad managed security service operation. SpiderLabs consultants not only perform pentests, but also feed and leverage threat intelligence from Trustwave’s global telemetry the company manages thousands of security devices and monitors networks around the world, providing insight into emerging threats. This means their testing often reflects the latest attacker trends. Trustwave is CREST certified and was one of the first to be accredited for various regions they have CREST UK, Asia, etc.. They also are a PCI QSA company and were deeply involved in setting standards for pen testing in compliance contexts. Another strong point is global delivery Trustwave has security hubs in North America, EMEA London, Warsaw, and APAC Singapore, Australia to serve clients 24/7. If a UK company has operations abroad, Trustwave can coordinate tests across regions easily. In pentesting, SpiderLabs is respected for technical prowess they have published many tools and exploits and thorough methodology. Moreover, because Trustwave handles a lot of incident response and threat research, they bring a real world attacker perspective. For instance, SpiderLabs often analyzes the latest breach malware that knowledge directly informs their red team exercises. Organizations looking for a big picture security provider that still has a sharp technical edge will find Trustwave compelling.
Key Strengths:
Potential Limitations: Trustwave, being a larger entity recently integrated into a new parent company as LevelBlue in 2026, can sometimes feel less personalized than a small boutique. Clients might experience more structured processes for scoping and communication, which some appreciate but others might find a tad impersonal. Pricing is generally enterprise oriented; they may not be the cheapest option for a small test. Also, because they offer many services, clients could encounter some cross selling e.g. after a pentest, you might be offered a managed service trial though you can always decline. Another limitation occasionally cited is that, for very niche cutting edge tests like fuzzing a new protocol, their team might have to schedule the specific expert from their global pool, which could introduce delays you might not always get the same small team continuity as you would with a tiny local firm. Lastly, as Trustwave has gone through corporate changes ownership changes, etc., some continuity could be in flux but SpiderLabs has remained a core strength throughout.
Best For: Enterprises and mid market companies that want a reputable, full service security provider to handle testing and possibly other security functions. Trustwave is especially fitting for organizations in retail, finance, or global industries that require both strong technical testing and alignment with standards like PCI, ISO 27001, etc. If your company could benefit from having both proactive and managed security handled by the same firm, or if you value threat intelligence being baked into your pentests, SpiderLabs is a top contender. It’s also a good choice for companies in the UK that have a presence in Asia or the Americas Trustwave can ensure consistent quality everywhere. In sum, go with Trustwave SpiderLabs if you’re looking for a proven team that merges hardcore hacking skills with the backing of a global security infrastructure.
| Company | Specialization | Best For | Region | Compliance Creds / Focus | Ideal Client Size |
|---|---|---|---|---|---|
| DeepStrike | Manual pentesting + continuous PTaaS platform cloud, app, API focus | All around security assurance Best Overall 2026 | UK London HQ, global delivery | Pursuing CREST OSCP/CISSP team; aligns reports to ISO 27001/PCI | Mid size tech firms to large enterprises needing flexibility |
| NCC Group | Enterprise scale, full spectrum security services | Large regulated enterprises, government | Global UK origin | CREST, CHECK; ISO 17025 lab; ISO 27001 certified | Large enterprises hundreds/thousands of assets |
| Pen Test Partners PTP | Deep dive boutique pentesting; IoT/OT expertise | Critical infrastructure, elite testing needs | UK Buckingham HQ, US/EU offices | CREST, CHECK; CBEST/TIBER certified; OSCP/OSWP staff | Mid to large orgs needing specialized expertise |
| Nettitude LRQA | Pentesting + compliance integration | Regulated industries finance, gov, etc. | UK Midlands HQ, global via LRQA | CREST, CHECK; PCI QSA, ISO 27001 auditors on team | Mid to large enterprises with heavy compliance needs |
| Bulletproof | Affordable pentests + 24/7 SOC for SMBs | SMBs and mid market needing security + compliance | UK London HQ | CREST accredited; Cyber Essentials certifier; ISO 27001 | Small to mid size businesses including startups |
| Secarma | Adversary simulations & advanced red teaming | Highly mature orgs for APT level drills | UK Manchester HQ | CREST, CHECK; exploits & tools developed in house | Mid to large organizations with mature security programs |
| BAE Systems AI | Defense grade cyber solutions consulting + tech | High assurance security programs defense, critical infra | Global UK HQ; 40+ offices | NCSC Certified; NATO/defense cleared teams | Large enterprise/government |
| Kroll Redscan | Offensive security + MDR combined | Organizations seeking pentest + continuous monitoring | Global London UK presence | CREST accredited; strong incident response practice | Mid size to large esp. those without in house SOC |
| IOActive | Hardware, IoT, and embedded system security | Product companies; critical system owners | Global USA HQ; UK & intl. labs | Follows industry safety standards UL, etc.; niche certs if needed per project | Enterprise / tech vendors esp. with hardware/IoT |
| Trustwave SpiderLabs | Threat intel–powered pentesting global MSSP backbone | Firms seeking security testing plus threat insight | Global USA HQ; UK & worldwide offices | CREST; PCI QSA; SOC 2 Type II for services | Mid size to large enterprises esp. needing MSSP synergy |
One important consideration when choosing a penetration testing partner is whether you’re better served by a large enterprise provider or a smaller boutique firm. Both have advantages, and the right choice depends on your organization’s size, culture, and needs. Here’s a breakdown to help guide that decision:
When Large Firms Make Sense: If you are a big enterprise with a broad attack surface, multiple concurrent projects, and strict compliance demands, a larger firm like NCC Group, BAE, or Bishop Fox global player can offer the capacity and range you need. These providers have extensive resources they can spin up multiple testing teams to hit tight deadlines and cover diverse technologies in parallel. They also tend to have well established processes and reporting suitable for formal audits and executive consumption. Large firms can often support multi year engagements, providing continuity as your business grows. They might also have additional services incident response, cloud consulting, etc. that an enterprise can leverage as a one stop shop. For a Fortune 500 type company with mature processes, the credibility and scale of a big name firm can satisfy due diligence for stakeholders. Additionally, big providers usually carry substantial insurance and legal frameworks which large enterprises often require of vendors.
When Boutique Firms Outperform: Smaller or boutique pentesting firms like DeepStrike, PTP, Secarma, etc. often punch above their weight in expertise and service. If you value a highly customized approach, direct access to senior experts, and flexibility, boutiques are extremely compelling. SMBs, in particular, benefit from the personal touch: the testing team you meet during scoping will likely be the ones doing the work, and they’ll tailor their approach to your specific environment rather than follow a rigid template. Boutiques can also be more agile scheduling may be faster, and they can adapt on the fly if you need to change scope or dig deeper into an issue discovered mid test. For organizations with niche needs or those who want the absolute top specialist in a given area, a boutique is often founded or staffed by those niche experts. For example, if you run a crypto exchange and want a security review, a smaller firm that specializes in blockchain security could provide more insight than a generic big firm. In short, boutiques excel at deep expertise, creativity, and client focus, which can result in a more meaningful test especially for unique environments.
Cost vs Value Trade offs: Budget is a reality in this decision. Large firms typically have higher rates, reflecting their overhead and brand prestige. However, they might accomplish more in a fixed time due to having bigger teams and refined methods so the value can be there if you fully utilize their capabilities e.g. needing 10 apps tested simultaneously across different countries. Boutiques might be more cost effective for smaller scopes you’re not paying for fancy offices or massive sales teams, and they often work with you to maximize value by focusing on your biggest risks. Be cautious of extremely low cost providers often very small or new firms if a quote seems much lower than others, ensure it’s not just a vuln scan or a shallow test. That said, many boutiques deliver high value per dollar by concentrating on impact and avoiding unnecessary process frills.
Risk Tolerance and Trust: Enterprise security leaders sometimes feel safer with a large firm because there’s a perceived lower risk: an established reputation, lots of resources if something goes wrong, and formal contracts/SLA assurances. SMBs might lean towards boutiques because trust is built person to person you often know exactly which expert is testing your systems maybe even the company’s founder. It’s worth noting that both large and small reputable firms maintain strict confidentiality and professionalism. If your risk tolerance is low say you’re a bank worried about any data exposure you might opt for a well known firm with decades of track record and deep insurance coverage. Conversely, if your priority is to uncover as much as possible and you’re willing to work with a perhaps more unconventional team, a boutique or even a vetted crowdsourced platform like Synack can yield great results by bringing diverse attacker mindsets.
Mix and Match Strategy: Many organizations actually use a combination of providers. For example, a company might use a big firm for annual compliance tests to satisfy auditors and execs, and a boutique for more frequent or specialized testing to dig into areas the annual test didn’t cover deeply. Others use crowdsourced testing platforms for continuous coverage, plus a consulting firm for high level engagements or strategic insights. This layered approach can offer the best of both worlds broad coverage plus deep dives. The key is to manage knowledge transfer between providers sharing previous findings, maintaining a consistent risk register and avoid gaps or overlaps.
There’s no one size fits all answer. Enterprises should not automatically dismiss boutiques, and SMBs shouldn’t assume big firms are out of reach. Focus on the criteria that matter to you: scope, expertise, relationship, budget. If you need breadth, scalability, and a one stop partner, lean towards a larger firm. If you need highly specialized skills, personal service, or maximum value on a limited budget, a boutique may be better. Ultimately, the best penetration testing provider is one that becomes a trusted advisor in your security journey whether that’s a team of 10 or 1000 what matters are the results they deliver and the confidence they instill.
Penetration testing costs can vary widely based on scope and depth. A simple test like a basic web app or external network scan for a small business might start in the low thousands of pounds, whereas a comprehensive engagement multiple apps, network segments, and a full red team for an enterprise can run tens of thousands of pounds. Typical pricing models are either fixed per engagement or daily rates e.g. £800 £1200 per tester day for skilled consultants in the UK. Be wary of quotes that are significantly lower than average ensure you understand what is and isn’t included. It’s also useful to factor in value, not just sticker price: a slightly more expensive firm that finds critical issues and provides remediation help can save money in the long run versus a cheaper test that misses important vulnerabilities. Always get a detailed scope and quote breakdown so you can compare providers on an apples to apples basis.
This depends on the scope and type of test. A small scale pentest e.g. a single web application or a small office network might be completed in 1–2 weeks including reporting. Larger tests multiple sites/apps or an internal network for a big company often take 4–6 weeks. Full red team simulations can span 8–12 weeks or even longer, especially if they involve multi month covert operations. Keep in mind, the timeline includes planning and scoping, the active testing period, and report generation. If you have a deadline like a compliance audit date, communicate that to the provider some can add resources to finish faster if needed. Also, factor in time for remediation and retesting of critical issues afterward. Quality testing is not a rush job; beware providers claiming to do extremely quick turnarounds on complex tests, as they might be cutting corners.
A professional pentest report should include an executive summary high level risks and recommendations for management, a detailed list of findings each vulnerability with description, severity, impacted systems, evidence/proof of concept, and remediation guidance, and often an appendix with technical data like output from tools, screenshots, or code snippets. The report should prioritize issues by risk criticality, so you know what to fix first. Good reports map findings to frameworks or compliance requirements e.g. OWASP Top 10 category, CVSS score, PCI requirement, etc. relevant to you. Many firms also offer a live debrief meeting or walkthrough of the results to ensure you understand them. Some deliver additional artifacts like raw data tool output, traffic logs on request. Increasingly, providers may supply results via a portal or dashboard especially PTaaS platforms for easy tracking of remediation. In any case, actionability is key expect clear guidance on how to fix or mitigate each finding, not just a generic statement of the problem.
Certifications and accreditations are a useful indicator of a provider’s baseline quality, but they are not the only factor. CREST and similar schemes like TigerScheme, Cyber Essentials Plus for certain scopes ensures the company meets certain standards and tester qualifications choosing a CREST certified firm is wise if you have compliance needs or want a vetted provider. Individual certs like OSCP, OSWE, CISSP indicate the skill and knowledge of team members. That said, they should complement a provider’s demonstrated experience and methodology, not replace it. A firm that lacks formal certs might still be excellent if their team has strong track records some boutique firms opt out of CREST due to cost, for example. On the flip side, a firm loaded with certs could still deliver a poor engagement if they rely solely on automated tools or junior staff. In summary, look for a balance: solid credentials and a clear, transparent testing methodology with expert human effort. Use certs as one data point especially CREST or CHECK if you’re UK government or finance sector, as those may be required but also evaluate past work, client references, and how they communicate during scoping. Remember, tools automated scanners, etc. are used by virtually all testers, but the magic is in the manual techniques and creative thinking on top of those tools.
At minimum, most organizations should have an annual penetration test of critical systems. However, more frequent testing is recommended if you have a high change rate or threat exposure. Many mid sized companies are moving to semi annual or quarterly testing cycles for key applications especially customer facing web and mobile apps that get updated often. In addition, whenever there’s a major change deployment of a new application, a significant infrastructure upgrade, moving to cloud, etc., you should consider a pentest on the new environment, even if it’s off cycle. Some compliance regimes PCI DSS, for example require at least annual tests and after major changes. Beyond scheduled tests, continuous testing approaches are emerging Pentest as a Service platforms or bug bounty programs can provide ongoing coverage in between formal tests. Ultimately, the cadence should align with your risk profile: if you’re a bank or a healthcare provider high sensitivity data, more frequent testing and perhaps continuous monitoring is warranted. If you’re a small business with a mostly static IT environment, annual might suffice. Also, don’t forget to re test after fixing high risk findings a penetration test’s value is in remediation, so verify that your fixes were effective, either via a follow up test or vulnerability scan.
These terms sometimes get used interchangeably, but they actually refer to different levels of assessment. A penetration test is typically a goal oriented security evaluation of specific systems for example, testing a web application and its supporting network for vulnerabilities. It’s usually overt you know it’s happening and has a defined scope and depth. A red team exercise, on the other hand, is a simulated attack scenario against your organization as a whole, often with only a few people in the organization aware it’s a test. Red teaming is more adversarial and open-ended the red team attempts to achieve certain objectives like access sensitive data or disrupt operations by any means a real attacker would, across digital, physical, and social engineering domains. It tests not just systems, but also your people and processes including detection and response. Red teams typically avoid detection, working over a longer period, whereas a pentest is more about finding technical vulnerabilities within a set time. Think of a pentest as a proactive security inspection and a red team as a full scale attack simulation. Both are valuable; many organizations start with pentesting to shore up obvious holes, then graduate to red teaming to test overall resilience. It’s important to clarify what you want with your provider if you ask for a red team but really needed a deep pentest, or vice versa, you might misalign expectations. Both need clear rules of engagement red teams especially, to ensure safety.
Selecting a penetration testing provider is a significant decision you’re entrusting them to ethically hack your systems and guide you in fixing weaknesses. In compiling this list of top UK providers for 2026, we’ve strived to remain neutral and research driven. Each of these companies brings something unique to the table, and the best choice will depend on your specific needs, risk appetite, and organizational context. A fintech scale up might lean toward a boutique like DeepStrike for its agile partnership approach, whereas a major bank might opt for the extensive resources of NCC Group or BAE Systems. Some companies may even engage multiple providers to leverage different strengths.
Our rankings and profiles are intended to give you a head start in your evaluation. We have no direct affiliation or sponsorship with these vendors DeepStrike’s inclusion as Best Overall is based on the criteria outlined as it blends strong technical expertise with innovative delivery, and we’ve applied the same scrutiny to all others. Ultimately, the goal is to empower you as a buyer with the right questions to ask and factors to consider. By understanding each provider’s expertise, strengths, and limitations, you can approach the procurement process with confidence and due diligence.
Cyber threats in 2026 aren’t slowing down, and neither should your security testing. Whichever vendor you choose, ensure they align with your goals, communicate well, and challenge your defenses in a meaningful way. A great penetration testing partner doesn’t just deliver a report they become a trusted advisor helping you continually improve your security posture. Here’s to making informed decisions and keeping your organization one step ahead of attackers.
Ready to Strengthen Your Defenses? The threats of 2026 demand more than just awareness; they require readiness. If you're looking to validate your security posture, identify hidden risks, or build a resilient defense strategy, DeepStrike is here to help. Our team of practitioners provides clear, actionable guidance to protect your business. Explore our Penetration Testing Services to see how we can uncover vulnerabilities before attackers do. Drop us a line, we’re always ready to dive in.
About the Author: Mohammed Khalil is a Cybersecurity Architect at DeepStrike, specializing in advanced penetration testing and offensive security operations. With certifications including CISSP, OSCP, and OSWE, he has led numerous red team engagements for Fortune 500 companies, focusing on cloud security, application vulnerabilities, and adversary emulation. His work involves dissecting complex attack chains and developing resilient defense strategies for clients in the finance, healthcare, and technology sectors.
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