Compliance audit firms in the United Kingdom

CREST-accredited UK cybersecurity and compliance provider offering penetration testing, managed security services, and regulatory consultancy to over 2,000 customers from its Stevenage headquarters.

CREST, CHECK, and CBEST accredited UK consultancy within Lloyd's Register, delivering premium penetration testing for government and critical infrastructure.

ISO/IEC 27001 certification audits and information security training from the UK national standards body, which also certifies quality, safety and medical devices.

Testing and certification group that helps vehicle makers and suppliers work towards ISO/SAE 21434 compliance.

The only organisation worldwide with a full suite of CREST accreditations. 250+ cybersecurity specialists operating in 55+ countries across pen testing, red teaming, and incident response.

UK compliance and cybersecurity consultancy, formerly IT Governance, offering CREST and NCSC CHECK penetration testing alongside governance, risk and compliance services.

Global enterprise cybersecurity consultancy founded in 1999 in Oxford, holding rare CREST STAR-FS accreditation and delivering penetration testing, red and purple teaming, and PCI QSA services across five international offices.

CREST-accredited UK cyber security and data protection consultancy offering penetration testing, ISO consultancy, and managed SOC services from offices across the UK and Ireland.

CREST-accredited Birmingham-based cyber security consultancy delivering penetration testing, social engineering assessments, and Cyber Essentials certification for public and private sector clients.

CREST-certified and PCI QSA penetration testing consultancy in London, delivering offensive security and compliance services across 25+ countries with research-driven expertise.

Manchester-based independent cybersecurity consultancy with over 20 years of experience delivering CREST and CHECK-accredited penetration testing, red teaming, and compliance certification services.

Award-winning CREST-certified managed cyber security and IT support provider with offices in Bristol, London, and Manchester, specialising in penetration testing and Microsoft security technologies.

CREST-accredited UK penetration testing consultancy based in Shropshire, delivering web application, API, infrastructure, cloud, mobile, and AI/LLM testing. A small specialist team, with a retest included in every engagement.

CREST-accredited Manchester-based cyber security firm delivering penetration testing, managed security services, and compliance consultancy across the UK, Europe, and the USA.

UK vehicle engineering and test centre offering threat modelling, CSMS support and security testing for vehicles.

Cyber security consulting covering strategy and governance, security transformation and cyber threat management, plus cyber managed services and cloud security from member firms.