Best CHECK-Approved Penetration Testing Companies (2026)
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: CREST pen testing companies · Pen testing companies in the UK
NCC Group
Global cybersecurity consultancy with CREST, CHECK, and CBEST accreditation, renowned for deep technical research and comprehensive penetration testing services.
Nettitude
CREST, CHECK, and CBEST accredited UK consultancy within Lloyd's Register, delivering premium penetration testing for government and critical infrastructure.
Pen Test Partners
The UK's largest independent security testing firm, renowned for IoT/OT research, CBEST red teaming, and CHECK/CREST-accredited penetration testing across all sectors.
PwC Cyber Security
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.
Dionach
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.
MDSec
Elite UK offensive security consultancy specialising in CBEST/STAR/TIBER red teaming, advanced adversary simulation, and CREST-accredited penetration testing for FTSE 100 clients.
Secarma
Manchester-based independent cybersecurity consultancy with over 20 years of experience delivering CREST and CHECK-accredited penetration testing, red teaming, and compliance certification services.
Cyberis
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.
Aristi
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.
Bridewell
Fast-growing CREST and CHECK-accredited UK cybersecurity consultancy with deep expertise in critical national infrastructure sectors.
Pentest People
CREST and CHECK-accredited UK penetration testing firm with an innovative SecurePortal platform and transparent pricing for mid-market organizations.
Best CHECK-Approved Penetration Testing Companies (2026), FAQs
What is CHECK accreditation?+
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.
Do I need a CHECK-approved pen tester?+
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.
How many CHECK-approved companies are there?+
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.