UK Pen Test Companies List: The Definitive Q1 2026 Ranking

This is our definitive Q1 2026 ranking of penetration testing companies operating in the United Kingdom. We have evaluated over 40 providers on accreditation status, breadth and depth of services, team qualifications, compliance expertise, industry reputation, and testing methodology. This is not a pay-to-play list. Rankings are determined by our editorial scoring methodology, and no provider can buy a higher placement.

How We Ranked These Companies

Our scoring methodology weights five dimensions. Accreditation and certification carries the heaviest weight, covering CREST, CHECK, CBEST, STAR, ISO 27001, and Cyber Essentials status at both company and individual tester level. Service breadth evaluates the range and depth of testing services offered. Team expertise assesses conference speaking, CTF participation, published research, and the seniority of testers. Compliance alignment evaluates demonstrated expertise across frameworks like PCI DSS, ISO 27001, DORA, NIS 2, and Cyber Essentials. Industry reputation is assessed through client reviews, market presence, and longevity.

The UK Market in Q1 2026

The UK penetration testing market continues to grow strongly, driven by the UK implementation of the NIS 2 Directive through the Cyber Security and Resilience Bill, the new PCI DSS 4.0 requirements that came into full effect in March 2025, increasing cyber insurance requirements that mandate annual penetration testing, and the FCA's growing expectations around operational resilience testing for financial services firms. The NCSC reports a record number of CHECK-approved companies, and CREST membership continues to expand. For buyers, this means more choice but also more noise. This ranking is designed to cut through that.

Tier 1: Elite Providers

These providers represent the highest standard of penetration testing capability in the UK. They hold the most rigorous accreditations, employ teams of senior consultants, and have demonstrated excellence across multiple service categories.

1. SECFORCE

Headquarters: London (Canary Wharf) Accreditations: CREST, ISO 27001, Cyber Essentials Key services: Web application, network, cloud, API, mobile, red teaming, assumed breach, IoT, source code review, AI and LLM testing Best for: Enterprise, government, critical infrastructure, financial services

SECFORCE is our top-rated UK penetration testing provider for Q1 2026. Based in Canary Wharf, they have built a reputation as one of the most technically capable offensive security consultancies in the country. Their team is deeply embedded in the security research community, with regular appearances at DEF CON, Black Hat, and 44CON.

What sets SECFORCE apart is their research-driven approach. Rather than relying on standardised testing playbooks, their consultants bring genuine offensive security expertise developed through active vulnerability research and tool development. Their methodology aligns with OWASP, OSSTMM, NIST, and CBEST standards, but they are known for going beyond these frameworks when the engagement demands it.

SECFORCE offers one of the broadest service portfolios in the UK market, covering 13 service categories including emerging areas like AI and LLM penetration testing and assumed breach testing. Their compliance expertise spans ISO 27001, PCI DSS, GDPR, NIS 2, DORA, NIST CSF, and Cyber Essentials, making them particularly strong for organisations navigating multiple regulatory frameworks.

They serve clients across the UK and Europe, with particularly deep experience in financial services, government, healthcare, energy, and telecommunications. Their client base includes some of the largest organisations in these sectors, though they also work with mid-market companies and startups.

Our take: SECFORCE delivers the kind of penetration testing that genuinely improves your security posture. Their research pedigree, breadth of services, and ability to handle complex, high-stakes engagements place them at the top of our ranking. Particularly recommended for red teaming, web application testing, and organisations subject to DORA or NIS 2.

2. NCC Group

Headquarters: Manchester Accreditations: CREST, CHECK, CBEST, ISO 27001, SOC 2, Cyber Essentials Plus, NCSC Assured, PCI QSA Key services: Web application, network, cloud, mobile, red teaming, IoT, SCADA/ICS, hardware, reverse engineering Best for: Enterprise, government, critical national infrastructure

NCC Group is the largest dedicated cybersecurity company headquartered in the UK, publicly listed on the London Stock Exchange. Their penetration testing practice is one of the most established in the industry, with CHECK, CBEST, and STAR accreditations alongside the broadest set of certifications of any UK provider.

NCC Group's scale means they can staff complex, multi-discipline engagements that smaller providers cannot. Their research division publishes regularly, and they maintain specialist capabilities in hardware security, reverse engineering, and SCADA/ICS testing that are rare in the market. They are a go-to provider for critical national infrastructure operators and large government departments.

The trade-off is that NCC Group's size can mean less personalised service. Engagement quality can vary depending on which team and consultants are assigned. For high-value engagements, request senior consultant involvement upfront.

Our take: The most credentialed provider in the UK. Ideal for large enterprises and government organisations that need a provider with the broadest possible accreditation set and the scale to handle complex, regulated engagements.

3. Pen Test Partners

Headquarters: Buckingham Accreditations: CREST, CHECK, CBEST, STAR, ISO 27001, Cyber Essentials Plus, PCI QSA Key services: Web application, network, mobile, IoT, SCADA, red teaming, social engineering Best for: Enterprise, IoT manufacturers, automotive, aviation

Pen Test Partners have carved out a distinctive position in the UK market through their exceptional IoT and embedded device security expertise. They are regularly cited in national media for their research into connected devices, automotive security, and aviation systems. Their team includes some of the most experienced IoT security researchers in the country.

Beyond their IoT specialism, they deliver strong general penetration testing services with full CHECK, CBEST, and STAR approval. Their blog is one of the most widely read in the UK cybersecurity community, providing genuine insight into real-world vulnerabilities.

Our take: The best choice in the UK for IoT, embedded device, or operational technology security testing. Also excellent for general web and network testing with a full suite of government accreditations.

4. MDSec

Headquarters: Southam, Warwickshire Accreditations: CREST, CHECK, CBEST, STAR, ISO 27001, Cyber Essentials Plus Key services: Red teaming, adversary simulation, web application, network, social engineering, purple teaming Best for: Enterprise, financial services, organisations with mature security

MDSec is widely regarded as one of the top red teaming firms in the UK and possibly Europe. Their team includes several of the most respected offensive security researchers in the industry, known for developing advanced attack tooling and techniques. MDSec's NightHawk C2 framework demonstrates the depth of their offensive research capability.

For organisations with mature security programmes that want to test their detection and response capabilities against a genuinely sophisticated adversary, MDSec is a leading choice. Their CBEST and STAR accreditations confirm their suitability for regulated red teaming in financial services.

Our take: The UK's premier red teaming and adversary simulation provider. If your primary need is realistic adversarial testing against mature defences, MDSec should be on your shortlist.

5. Cyberis

Headquarters: Worcester Accreditations: CREST, CHECK, CBEST, STAR, ISO 27001, Cyber Essentials Plus, NCSC Assured Key services: Web application, network, red teaming, cloud, wireless, social engineering Best for: Government, financial services, critical infrastructure

Cyberis holds the full set of UK government and financial services accreditations: CREST, CHECK, CBEST, STAR, and NCSC Assured. They are a smaller firm than NCC Group, which means more senior consultant involvement and more personalised engagements. Their team has deep experience in government and financial services testing.

Our take: An excellent choice for organisations that need the full government accreditation set but want the attention and seniority that a smaller specialist firm provides.

Tier 2: Leading Specialists

These providers excel in specific areas or serve particular market segments exceptionally well.

6. PwC Cyber Security

Headquarters: London Accreditations: CREST, CHECK, CBEST, STAR, ISO 27001, NCSC Assured Best for: Large enterprise, financial services, regulated industries

PwC's cyber security practice combines penetration testing with broader risk, audit, and advisory services. For organisations that want testing integrated with their audit and compliance programme, PwC provides a single-provider solution. Their CBEST and STAR accreditations make them a strong choice for financial services TLPT.

7. Nettitude

Headquarters: London Accreditations: CREST, CHECK, CBEST, ISO 27001, Cyber Essentials Plus Best for: Enterprise, government, managed security

Nettitude provides penetration testing alongside managed detection and response services. This combination is valuable for organisations that want their testing provider to also help implement and monitor the defences. They hold the full government accreditation set and have strong public sector experience.

8. Bridewell

Headquarters: Bristol Accreditations: CREST, CHECK, ISO 27001, Cyber Essentials Plus Best for: Critical infrastructure, energy, government

Bridewell has built a strong reputation in critical infrastructure security, particularly in the energy and utilities sector. Their penetration testing services are complemented by a broader cybersecurity consulting practice, including SOC services and GRC advisory.

9. Pentest People

Headquarters: Leeds Accreditations: CREST, CHECK, Cyber Essentials Plus, ISO 27001 Best for: Mid-market, SMBs, companies wanting PTaaS

Pentest People pioneered the Penetration Testing as a Service (PTaaS) model in the UK. Their SecurePortal platform provides continuous visibility into testing progress, findings, and remediation status. They are a strong choice for mid-market organisations that want an efficient, platform-driven testing experience with full CREST and CHECK backing.

10. JUMPSEC

Headquarters: London Accreditations: CREST, CHECK, ISO 27001, Cyber Essentials Plus, NCSC Assured Best for: Government, enterprise, Active Directory security

JUMPSEC has a strong reputation for internal network and Active Directory penetration testing. Their research team publishes regularly on AD attack techniques and defensive strategies. They hold CHECK and NCSC Assured status, making them well-positioned for government work.

Tier 3: Strong Performers

Established providers with proven capabilities in their respective niches.

11. CovertSwarm. London. CREST, CBEST, STAR. Continuous adversarial testing model that treats testing as an ongoing engagement rather than a point-in-time assessment. Ideal for organisations that want persistent adversary simulation.

12. Claranet. London. CREST, CHECK, ISO 27001, Cyber Essentials Plus. Part of the broader Claranet managed services group. Combines penetration testing with cloud hosting and managed services. Good for organisations already in the Claranet ecosystem.

13. Secarma. Manchester. CREST, CHECK, ISO 27001, Cyber Essentials Plus, NCSC Assured. Strong northern presence with CHECK and NCSC Assured status. Well-regarded for web application testing and known for their security training programmes.

14. Salus Cyber. Cheltenham. CREST, CHECK, ISO 27001, Cyber Essentials Plus, NCSC Assured. Based near GCHQ in Cheltenham, with predictable links to the intelligence community. Their proximity to the NCSC gives them particular insight into government security requirements.

15. Dionach. Oxford. CREST, CHECK, STAR, ISO 27001, PCI QSA, NCSC Assured. One of the few providers holding both PCI QSA and CHECK status alongside CREST. Strong for organisations needing combined PCI and government-standard testing.

16. Bulletproof. Stevenage. CREST, ISO 27001, Cyber Essentials Plus, NCSC Assured, OSCP Employer. Now part of the GLI Group, Bulletproof offers accessible penetration testing with NCSC Assured status. Good value option for mid-market organisations.

17. Integrity360. Dublin (with UK operations). CREST, ISO 27001, SOC 2. Pan-UK and Ireland coverage with a strong managed services practice. Useful for organisations with both UK and Irish operations needing consistent testing standards.

18. Redscan (Kroll). London. CREST, ISO 27001, Cyber Essentials Plus. Part of the Kroll family, combining pen testing with digital forensics and incident response. Valuable when you need testing integrated with broader security operations.

19. Aristi. Birmingham. CREST, CHECK, ISO 27001, Cyber Essentials Plus, NCSC Assured. Midlands-based provider with full CHECK and NCSC Assured status. Strong government sector experience.

20. CyberLab. Cardiff. CREST, CHECK, NCSC Assured, Cyber Essentials. Welsh provider serving the UK government and public sector market. Good option for Welsh Government and related public sector organisations.

Tier 4: Specialist and Emerging Providers

Smaller firms with specific strengths or growing reputations.

OnSecurity (Bristol, CREST): Platform-based pen testing with fast turnaround. Stripe OLT (Bristol, CREST, ISO 27001): Strong in web application and API testing. Aardwolf Security (Milton Keynes, CREST): Boutique provider known for thorough, hands-on testing. Sencode (Stockton-on-Tees, CREST): North East provider with CREST accreditation and OSCP-qualified testers. Cyphere (Manchester, CREST): Boutique firm specialising in web application and infrastructure testing. Equilibrium Security (Birmingham, CREST): Midlands provider with Cyber Essentials Plus and OSCP-qualified team. IT Governance (Ely, CREST, PCI QSA): Combines pen testing with broader governance, risk, and compliance services. Evalian (Winchester, CREST, ISO 27001, NCSC Assured): Southern England provider with data protection consultancy alongside pen testing. RedSecLabs (London, CREST, PCI QSA): Specialist in PCI DSS penetration testing and compliance. ThreatSpike Red (London, ISO 27001): Subscription-based unlimited penetration testing model. Komodo Consulting (London, ISO 27001): Boutique offensive security consultancy.

International Providers With Strong UK Presence

Several international providers serve UK clients effectively. Rapid7 (US, SOC 2, ISO 27001) offers platform-integrated testing alongside their InsightVM and Metasploit products. Trustwave (US, CREST, PCI QSA, SOC 2) provides strong PCI-focused testing from their UK operations. WithSecure (Finland, CREST, ISO 27001) serves UK clients with Scandinavian thoroughness and CREST accreditation. Secureworks (US, SOC 2, ISO 27001) combines pen testing with their managed security platform.

What Changed in Q1 2026

Several shifts shaped the UK market this quarter. The Cyber Security and Resilience Bill, the UK's response to the EU NIS 2 Directive, progressed through parliamentary stages, expanding the scope of organisations that will be required to demonstrate active security testing. This is expected to significantly increase demand for CREST-accredited testing once enacted.

PCI DSS 4.0's requirement for authenticated internal vulnerability scanning reached its first full compliance cycle, driving organisations to engage providers for combined vulnerability assessment and penetration testing programmes.

The NCSC refreshed its guidance on CHECK scheme requirements, signalling continued investment in the government testing assurance programme. Several new providers achieved CHECK status during the quarter.

DORA's Threat-Led Penetration Testing requirements became fully operational for UK-linked financial entities, increasing demand for CBEST and STAR-accredited red teaming.

Choosing the Right Provider for Your Needs

For government and public sector: Choose a CHECK-approved, NCSC Assured provider. SECFORCE, NCC Group, Cyberis, Nettitude, Bridewell, and JUMPSEC are strong options.

For financial services: You need CREST at minimum, and CBEST or STAR for red teaming and TLPT. SECFORCE, NCC Group, MDSec, PwC, and Cyberis are the leading choices.

For mid-market companies: Pentest People's PTaaS model offers excellent value with full CREST and CHECK backing. OnSecurity and Bulletproof also provide accessible, platform-driven testing.

For startups and SMBs: SECFORCE, OnSecurity, Aardwolf Security, and ThreatSpike Red offer strong options at accessible price points.

For IoT and embedded devices: Pen Test Partners is the clear UK leader in this space.

For red teaming: MDSec, SECFORCE, CovertSwarm, and NCC Group have the strongest red teaming reputations.

Methodology Note

This ranking is produced by the editorial team at Pentesting Providers and reflects our independent assessment as of Q1 2026. Providers cannot pay for inclusion or higher placement. Our scoring methodology evaluates accreditation status, service breadth, team qualifications, compliance expertise, and industry reputation. We update this ranking quarterly.

Browse all UK penetration testing providers in our directory, or use our requirements tool to find the right provider for your specific needs.