CHECK is a UK government scheme operated by the National Cyber Security Centre (NCSC) that approves companies to conduct penetration testing of government systems. CHECK-approved companies have undergone rigorous assessment of their testing capabilities, staff qualifications, and security handling procedures.
If you are a UK government department, public sector organisation, or critical national infrastructure operator, you may be required to use a CHECK-approved penetration testing provider. The providers below hold CHECK approval alongside other accreditations.
Related: Public sector penetration testing companies · CREST pen testing companies · Pen testing companies in the UK
CREST and CHECK-accredited UK penetration testing and managed security provider formed in 2026 from Pentest People, Bulletproof, and Target Defense, with CREST STAR/TLPT-FS capability and the GuardNest vulnerability management platform.
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.
Global Big Four professional services firm delivering CREST, CHECK, and CBEST-accredited penetration testing and red teaming services from London, serving the UK's largest enterprises and regulated organisations.
Elite UK offensive security consultancy specialising in CBEST/STAR/TIBER red teaming, advanced adversary simulation, and CREST-accredited penetration testing for FTSE 100 clients.
Full-service London-based cybersecurity consultancy with CREST, CHECK, and NCSC accreditations delivering offensive testing, managed detection, and strategic advisory services.
Manchester-based independent cybersecurity consultancy with over 20 years of experience delivering CREST and CHECK-accredited penetration testing, red teaming, and compliance certification services.
CREST and CHECK-accredited UK penetration testing consultancy with CBEST approval, specialising in infrastructure, application, and simulated attack assessments across the public and private sectors.
CHECK and CREST-accredited Birmingham-based cyber security consultancy with over 15 years of experience delivering penetration testing, red teaming, and OT security assessments for government and private sector clients.
Fast-growing CREST and CHECK-accredited UK cybersecurity consultancy with deep expertise in critical national infrastructure sectors.
Award-winning Cheltenham-based cybersecurity consultancy with NCSC CHECK Green Light status and CREST approval, specialising in defence, government, and critical national infrastructure security.
CREST and CHECK-accredited European managed services provider delivering penetration testing with deep infrastructure and cloud hosting expertise.
Cardiff-based CREST and CHECK-accredited cyber security company delivering penetration testing, red teaming, and OT security assessments as part of the Chess Group.
CHECK is a UK government scheme run by the NCSC (National Cyber Security Centre) that approves companies to test government and public sector systems. CHECK-approved testers have demonstrated high levels of competence through rigorous NCSC assessment.
CHECK approval is typically required for testing UK government systems, critical national infrastructure, and some public sector organisations. For commercial testing, CREST accreditation is the more common requirement.
There are approximately 30-40 CHECK-approved companies in the UK. The NCSC maintains the current list. All CHECK companies must also maintain CREST accreditation.