Penetration Testing Providers in United Kingdom

Europe

UK-based penetration testing providers, many holding CREST, CHECK, and CBEST accreditations recognised by the National Cyber Security Centre (NCSC).

The UK has one of the most mature pen testing markets globally, with providers serving financial services under CBEST, government under CHECK, and commercial organisations across all sectors.

15 providers
Top UK ProviderElite TestersResearch-Driven
SECFORCE logo

SECFORCE

Leading UK offensive security consultancy based in Canary Wharf, delivering CREST-accredited penetration testing and adversary simulation to organisations with the most demanding security requirements.

95
Score
LOCLondon, United Kingdom
Web ApplicationNetworkMobile App+9
CRESTISO 27001Cyber Essentials
Best UK ProviderBest for EnterpriseResearch Leaders
NCC Group logo

NCC Group

Global cybersecurity consultancy with CREST, CHECK, and CBEST accreditation, renowned for deep technical research and comprehensive penetration testing services.

75
Score
LOCManchester, United Kingdom
Web ApplicationNetworkMobile App+13
CRESTCHECKCBEST+6
Nettitude logo

Nettitude

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

64
Score
LOCLondon, United Kingdom
Web ApplicationNetworkMobile App+10
CRESTCHECKCBEST+2
Trustwave logo

Trustwave

Global managed security provider with the elite SpiderLabs penetration testing team and deep PCI DSS compliance expertise.

57
Score
LOCChicago, Illinois, United States
Web ApplicationNetworkMobile App+7
PCI QSAISO 27001SOC 2+1
Bridewell logo

Bridewell

Fast-growing CREST and CHECK-accredited UK cybersecurity consultancy with deep expertise in critical national infrastructure sectors.

56
Score
LOCBristol, United Kingdom
Web ApplicationNetworkCloud+7
CRESTCHECKISO 27001+1
Pentest People logo

Pentest People

CREST and CHECK-accredited UK penetration testing firm with an innovative SecurePortal platform and transparent pricing for mid-market organizations.

55
Score
LOCLeeds, United Kingdom
Web ApplicationNetworkMobile App+7
CRESTCHECKCyber Essentials Plus+1
Mandiant logo

Mandiant

World-renowned cybersecurity firm now part of Google Cloud, delivering threat intelligence-led penetration testing and red teaming informed by front-line incident response experience.

53
Score
LOCReston, Virginia, United States
Red TeamingPurple TeamingNetwork+6
SOC 2ISO 27001FedRAMP 3PAO
WithSecure logo

WithSecure

Leading European cybersecurity firm offering penetration testing with deep expertise in EU regulatory compliance including GDPR, NIS 2, and TIBER-EU.

49
Score
LOCHelsinki, Finland
Web ApplicationNetworkCloud+7
CRESTISO 27001
Claranet logo

Claranet

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

48
Score
LOCLondon, United Kingdom
Web ApplicationNetworkMobile App+5
CRESTCHECKISO 27001+1
HackerOne logo

HackerOne

World's largest ethical hacker platform with over one million researchers, offering bug bounties and structured penetration testing to the US DoD and Fortune 500.

47
Score
LOCSan Francisco, California, United States
Web ApplicationAPIMobile App+3
SOC 2ISO 27001FedRAMP 3PAO
Integrity360 logo

Integrity360

CREST-accredited pan-European cybersecurity services provider delivering penetration testing and managed security from Dublin with a strong UK and Ireland presence.

44
Score
LOCDublin, Ireland
Web ApplicationNetworkMobile App+6
CRESTISO 27001SOC 2
CrowdStrike logo

CrowdStrike

Global cybersecurity leader leveraging world-class threat intelligence from the Falcon platform to deliver intelligence-led penetration testing and red teaming.

43
Score
LOCAustin, Texas, United States
Red TeamingNetworkWeb Application+5
SOC 2ISO 27001
IOActive logo

IOActive

Elite boutique security consultancy specializing in IoT, SCADA/ICS, embedded systems, and hardware security research with world-renowned researchers.

42
Score
LOCSeattle, Washington, United States
Web ApplicationNetworkIoT+7
OSCP Employer
Secureworks logo

Secureworks

Dell Technologies-backed cybersecurity firm with elite Counter Threat Unit intelligence informing enterprise penetration testing and adversary simulation.

41
Score
LOCAtlanta, Georgia, United States
Web ApplicationNetworkCloud+7
SOC 2ISO 27001
Aon Cyber Solutions logo

Aon Cyber Solutions

Cybersecurity consulting division of global insurance leader Aon, uniquely combining penetration testing with cyber risk quantification and insurance expertise.

36
Score
LOCLondon, United Kingdom
Web ApplicationNetworkCloud+5
ISO 27001SOC 2