Managed security service providers in the United Kingdom

Bondgate IT is a managed service provider founded in 1998.

Cyber advisory and managed security services, including managed extended detection and response, cloud security, digital identity and threat intelligence, from a global professional services network.

Littlefish provides managed IT services, cyber security, digital solutions, and data and AI services to organisations.

System Force IT provides managed IT support, cyber security, and Microsoft 365 services to UK SMEs.

CREST and CHECK-accredited European managed services provider delivering penetration testing with deep infrastructure and cloud hosting expertise.

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.

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.

London-based cybersecurity firm offering unlimited, fixed-price penetration testing and red teaming services with ISO 27001 certification and a unique subscription model.

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.

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.

Award-winning Cheltenham-based cybersecurity consultancy with NCSC CHECK Green Light status and CREST approval, specialising in defence, government, and critical national infrastructure security.

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

Corero Network Security provides automatic DDoS protection for businesses and service providers.

Cybersecurity consulting and managed services covering security transformation, incident response, data protection and privacy, identity and privileged access, and operational technology security.

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