Aardwolf Security
Cybersecurity company specializing in penetration testing; UK-based with a focus on web, network, and cloud security assessments, adhering to OWASP standards; 1 employee; Monthly visits: 30,811; Global rank: #895,021.
NCC Group
UK-based IT services and cybersecurity consulting company; specializes in penetration testing, security assessments, and managed security services with 1,161 employees and $412.5M annual revenue. Operates globally with a focus on cyber resilience, responsible business, and sustainability; founded in 1999, market cap GBP 506.6M.
DigitalXRAID
Cybersecurity company specializing in penetration testing and security services; provides CREST-accredited web and internal penetration testing with active attack simulation capabilities; based in the United Kingdom with 39 employees and $8.6M annual revenue.
Codigo Security
UK-based cybersecurity consulting company founded in 2018 with 2 employees; specializes in web application security, cloud security, and penetration testing; explicitly offers manual web application penetration testing aligned with OWASP, NIST, and SANS standards; registered at 71-75 Shelton Street, Covent Garden, London.
SECFORCE LTD
Cybersecurity consultancy specializing in offensive security assessments; provides penetration testing, red teaming, and security consulting with 29 employees, $27.3M revenue, founded in 2008, based in United Kingdom • Industry: Computer and Network Security; Founded 2008; 29 employees; Revenue: $27.3M; Headquarters: UK; Recognized for expertise in penetration testing, threat modeling, exploit development, and vendor-independent security assessments.
Clearfin Security
Cybersecurity company specializing in penetration testing, vulnerability assessment, phishing campaigns, and digital infrastructure security; based in London, UK, with 3 employees, focusing on affordable, effective security services for organizations.
Punk Security Limited
UK-based IT services and consulting company specializing in DevSecOps, cybersecurity, and cloud engineering; 6 employees, founded 2021, with a focus on penetration testing, governance support, and cloud security services.
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Closed Door Security
UK-based private cybersecurity company specializing in penetration testing, security assessments, engineering, and certification; CREST-accredited, partner of SBRC & Police Scotland, with 4 employees and 33.3% YoY growth; actively promotes penetration testing services through dedicated pages and certifications.
Cognisys
UK-based IT services and cybersecurity company specializing in penetration testing, security assessments, and compliance; 63 employees with 95.5% YoY growth; founded in 2017; CREST-accredited penetration testing services; headquartered in Leeds, UK.
DefenseLabs
UK-based private cybersecurity firm specializing in offensive security and penetration testing; offers adversary emulation, exploit development, threat modeling, vulnerability research, and AI-driven attack simulations; founded in 2025 with 2 employees; headquartered in London, UK.
Fidus Information Security
Fidus Information Security is a UK-based private cybersecurity company specializing in penetration testing and network security solutions; 4 employees, $5M revenue, founded 2017 in Cambridge, UK. They offer advanced pentest services, network and IoT security, and serve diverse sectors including public, legal, and healthcare.
Paul Reynolds Cyber Security
Cybersecurity firm based in Solihull, UK, with additional operations in Dubai, UAE; provides penetration testing (pentest) services including PTaaS and certified testing teams, emphasizing offensive security expertise.
Aptive Cyber Security
UK-based cybersecurity consultancy founded in 2011; specializes in penetration testing, vulnerability assessments, security hardening, and network security audits; serves UK and global clients; 15,008 monthly visits; global rank #1,649,321.
LRQA
UK-based risk management and certification company with 2,098 employees and $750.5M revenue; provides penetration testing services including CREST-certified and web application testing, with a focus on cybersecurity and quality assurance.
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A-listware
A-listware is a UK-based IT services and consulting firm with 29 employees, founded in 2017, specializing in remote engineering teams and cybersecurity, including penetration testing services with CREST accreditation; operates an R&D center in Ukraine and offers expertise in multiple programming languages and technologies.
Bramfitt Tech Labs
UK-based cybersecurity consultancy specializing in CREST-certified penetration testing services; recognized as a global provider of CREST-certified penetration tests, with a focus on cyber resilience and innovation.
Total Group International
UK-based private company in computer networking and cybersecurity; 14 employees, $3.6M revenue, founded 2000; offers IT security, support, cloud, and penetration testing services (TotalPenTest) with active case studies and dedicated solutions.
QinetiQ
British defence technology company based in Farnborough, Hampshire, UK; provides penetration testing services including CREST-certified security assessments and real-world attack simulations.
Jumpsec
UK cybersecurity firm Jumpsec Limited offers bespoke consultancy and CREST-certified penetration testing services, including application and threat-led pentests; based in London and Surrey, emphasizing technical excellence and expert-driven approaches.
Brigantia by Elovade
UK-based IT services and cybersecurity consulting company with 30 employees, founded in 1996; specializes in cybersecurity solutions, including penetration testing via Rootshell, and supports channel partners with recurring revenue growth; part of the Elovade Group, with a focus on security assessments, red team engagements, and managed services.
Resillion
UK-based IT services and consulting company specializing in quality engineering, cyber security, and media content; offers penetration testing services confirmed by NCSC CHECK certification, with 300 employees (+13.8% YoY growth), $25.4M annual revenue, and offices across North America, Europe, and Asia.
JAG SECURE®
IT services and consulting company specializing in cybersecurity and penetration testing; based in London, UK, with 1 employee; focuses on tailored security solutions and digital resilience.
Prism Infosec
Cybersecurity firm based in Cheltenham, UK, specializing in penetration testing, red teaming, and GRC services; provides assessments, testing, and response solutions to enhance security posture.
CyPro
CyPro is a UK-based private cybersecurity firm specializing in computer and network security, with 15 employees and 16.7% YoY growth since 2022. It explicitly offers penetration testing services that simulate attacks to uncover vulnerabilities, supporting high-growth companies in scaling their security capabilities and gaining client trust.
Blackfoot Cybersecurity
Cybersecurity company specializing in computer and network security, penetration testing, and compliance; 15 employees with +20.8% YoY growth; founded in 2008; headquartered in Welwyn Garden City, UK; offers services including installation, gas washing, ventilation, and equipment manufacturing; active in cyber security training and risk management.
Ascentor Ltd
Cybersecurity company specializing in cyber risk management, technical assurance, and penetration testing; 14 employees, $26.9M revenue, founded 2004 in West Malling, UK; offers CREST-certified pentest services, Cyber Essentials, and management consultancy, with a global ranking of #7,420,700 and UK rank #665,425.
Foresight Cyber
UK-based cybersecurity company specializing in penetration testing; offers dedicated pentest services as part of its cybersecurity assessments, with a registered London office at 71-75 Shelton Street, London WC2H 9JQ.
CyberProtect
CyberProtect is a UK-based cybersecurity firm providing advanced security solutions, including penetration testing, vulnerability assessments, and security simulations; headquartered in the United Kingdom with a focus on proactive vulnerability identification and defense enhancement.
Acora - IT, Cyber & AI
UK-based IT services and consulting company with 337 employees and $63.5M revenue; specializes in secure digital transformation and offers explicit penetration testing, red-teaming, and attack simulation services; operates in IT infrastructure, security, and cloud solutions.
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CyberQ Group
CyberQ Group is a UK-based private cybersecurity firm specializing in cyber protection and penetration testing services; 27 employees, founded in 2017, with $6.3M in funding, providing 24/7 global support and known for a reactive, technology-driven approach to cybersecurity.
Dionach
Cybersecurity firm based in Oxford, UK, specializing in penetration testing and security assessments; CREST-accredited with a comprehensive suite of security services. Part of Nomios; founded in the UK.
Cyber Vigilance
Cyber Vigilance is a UK-based cybersecurity firm headquartered in Guildford, UK; specializes in penetration testing services that identify vulnerabilities in infrastructure and applications, including automated pentesting capabilities through Horizon3.ai partnership.
Exploitr
UK-based cybersecurity firm specializing in penetration testing services; officially registered in Newport, Wales (Companies House 15939324); holds CREST Pathway Accreditation, confirming recognized credentials in pentest services.
Cambridge Cyber Advisers
UK-based cybersecurity company specializing in penetration testing and red teaming; offers real-world vulnerability assessments and active testing services; headquartered in Cambridge, UK.
Kocho
UK-based cybersecurity firm specializing in Microsoft identity, security, and cloud solutions; offers penetration testing services and security consulting; registered in England and Wales (company number 04308824), with a London office.
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Aristi Limited
Cybersecurity company based in Birmingham, UK, specializing in CREST-certified penetration testing services; headquartered in Birmingham, West Midlands, UK.
SEC-TEC LIMITED
UK-based cybersecurity firm founded in 1999; specializes in penetration testing, PSN Health Checks, and InfoSec services; headquartered in Erith, Kent, with active operations serving organizations worldwide.
CyberFortis Consulting
UK-based IT and cybersecurity consulting firm specializing in penetration testing, threat intelligence, risk assessments, and compliance services; 4 employees; founded 2019; offers explicit pentest services; serves clients across UK, EU, Australia, New Zealand, and USA.
Cyber Sense
Cyber Sense is a UK-based private cybersecurity firm specializing in penetration testing services, including internal, web application, and API assessments, with CREST registered testers and proactive threat intelligence; 2 employees, +25% YoY growth, founded in 2020, headquartered in London, UK.
Firesand Ltd
UK-based cybersecurity firm specializing in security solutions and penetration testing; headquartered in Milton Keynes, Buckinghamshire, with a registered office in Newport Pagnell, UK; offers security design, development, strategy, and assurance services.
Mothax Ltd
Application security testing company specializing in web, API, and mobile app security; provides penetration testing, training, and security consultancy services across the UK. Based in Cromford, UK, founded in 2012, with 1 employee, led by Gareth Watkin-Jones.
Secore Information Security
Cybersecurity company specializing in structured, quantitative security assessments for IT and OT systems; provides penetration testing services with real-world attack simulations; founded 2023, 6 employees, based in London, UK; active social media presence; 14.3% monthly workforce growth.
Exponential-e
UK-based IT services and consulting company providing secure cloud, connectivity, cyber, and voice solutions; 492 employees, $255.7M revenue, founded 2002, headquartered in London. Offers penetration testing, red team testing, and website security testing, with a focus on active cybersecurity testing and exploitation simulation.
Digital Interruption
UK-based cybersecurity consultancy in Manchester; provides penetration testing across web, mobile, API, and network environments with risk identification and remediation services.
Reliance Cyber
Reliance Cyber is a UK-based IT services and cybersecurity consulting company with 48 employees and $5M-$25M annual revenue; specializes in penetration testing, threat intelligence, incident response, and managed security services, with a focus on safeguarding organizations in the digital landscape.
Closed Door Security
UK-based cybersecurity firm specializing in penetration testing and security assessments; registered in the UK (SC585645), headquartered in Stornoway, UK; offers professional pentest services as highlighted on their website and supported by external sources.
CodeShield (Cyber Security)
UK-based cybersecurity firm specializing in penetration testing for web apps, networks, and cloud environments; 1 employee; focuses on threat detection and compliance (ISO, PCI, SOC2, Dstp).
Attack Vector Ltd
UK-based cybersecurity firm specializing in penetration testing; offers infrastructure, web app, cloud, social engineering, and mobile testing; registered in London with Company No. 14996130.
Sophos
Cybersecurity software development company based in the United Kingdom; 3,664 employees, $1B revenue, founded 1985, GBP2.8B market cap, $125M funding; offers endpoint, network, cloud security, and penetration testing services; serves 600,000 organizations globally with an AI-driven platform and expert-led services.
UK Pen Testing – A LevelUp Networks service
Cybersecurity company specializing in penetration testing and security assessments; based in London, UK, with services including Penetration Testing as a Service, Web Application Penetration Testing, Red Team, Cloud Security, Phishing, Firewall Audits, and Ransomware Assessments; explicitly confirmed UK address in London.
Laneden Ltd
Cybersecurity company specializing in penetration testing, threat simulation, and compliance testing; based in United Kingdom with 1 employee, founded in 2019. Offers services including penetration testing, social engineering, web app security, and infrastructure reviews, focusing on identifying security vulnerabilities and quantifying risks.
NeedSec Limited
UK-based cybersecurity company specializing in penetration testing; headquartered in London, with a registered office at 86-90 Paul Street, London, England. Provides security testing services to identify system vulnerabilities.
Pentest Limited
UK-based cybersecurity company founded in 2019; registered at 22 Great James Street, London, with company number 11925182; provides manual penetration testing, red teaming, and security consultancy services.
SecurityHQ
UK-based MSSP specializing in penetration testing, MDR, and bespoke cybersecurity services; recognized as a leader by KuppingerCole and Frost & Sullivan; offers 24/7 MXDR, security posture management, and vulnerability detection; CREST accredited.
SensePost
UK-registered ethical hacking team within Orange Cyberdefense; specializes in penetration testing and offensive security services; based in Maidstone, Kent, with official UK Companies House registration.
Techforce
UK-based cybersecurity firm headquartered in Aberdeen and Edinburgh; offers penetration testing, cyber maturity assessments, Cyber Essentials certification, virtual CISO, vulnerability management, and managed security services; specializes in protecting businesses from cyber threats with expert consulting and testing solutions.
Intertek
Intertek is a UK-based provider of quality assurance and testing services, headquartered in London at 33 Cavendish Square. The company explicitly offers penetration testing and cybersecurity assessment services, including vulnerability testing and manual penetration tests, across multiple industries.
4N6
IT services and consulting company specializing in cybersecurity, troubleshooting, diagnostics, post-incident reviews, and digital forensics; offers full penetration testing services including active exploitation, vulnerability analysis, and remediation; based in London, UK with 1 employee, 1,122 monthly website visits, and ranked #11,322,919 globally.
BSI Cyber Consulting
Cybersecurity company specializing in penetration testing, red team assessments, and information security services; supports CREST-certified pentest offerings and detailed testing procedures; 2 employees, $9.44M revenue, headquartered in Cambridge, UK.
Socura
Cybersecurity company specializing in managed detection and response, digital forensics, incident response, and rapid response services; CREST-approved with formal penetration testing credentials, collaborating with partners like Rootshell Security for pentest services; based in Cardiff, UK, with 30 employees and 32.3% YoY growth.
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Bema Cyber Tech Ltd
UK-based IT service provider specializing in cybersecurity; offers penetration testing services; registered in London with a UK office at 124 City Road; provides solutions for public and private sectors to achieve Cyber Essentials certifications.
Sodium Cyber Ltd
Cybersecurity consultancy specializing in penetration testing and security assessments; based in Worcestershire, UK with 2 employees, founded in 2020. Offers web application and infrastructure pentests, cloud security, secure code reviews, and maritime systems security; 208 monthly website visits.
PlutoSec
UK-based cybersecurity provider specializing in penetration testing; emphasizes leadership in UK cybersecurity market with multiple UK addresses and branding; offers comprehensive cybersecurity solutions across major UK cities.
ROSCA Technologies
UK-based cybersecurity consultancy specializing in CREST penetration testing for networks, applications, and cloud; located in London, with a focus on strategic cybersecurity management and testing services.
Mongoose Cyber Security
UK-based cybersecurity company founded in December 2022; provides comprehensive penetration testing services including external, web app, social engineering, internal, wireless, and physical testing; CREST-accredited for formal pentest capabilities; registered in Wilmslow, England (Unit 3, Building 2, The Colony Wilmslow, SK9 4LY).
Syn-Star IT Support
UK-based IT services and consulting company founded in 2002; 13 employees, $2.4M revenue; specializes in business IT support, cybersecurity, and penetration testing with dedicated pentest services; serves SMEs with a focus on reliable, end-to-end IT solutions and security.
Simple IT Distribution Ltd
UK-based software development firm founded in 2015 with 2 employees; provides penetration testing and vulnerability management services using tools like Metasploit, demonstrating active security testing capabilities; has 1,096 monthly website visits and a global rank of #11,686,164.
SIBR
Cybersecurity consultancy and penetration testing firm based in London, UK; 3 employees, founded 2021; offers services including penetration testing, vulnerability management, and cloud security to SMEs; over 20 years of combined security experience.
Bluefort Security
UK-based cybersecurity provider specializing in penetration testing; offers automated pentest solutions like Pentera and holds CREST certification credentials, demonstrating active and certified pentest capabilities • 50-100 employees; Cybersecurity; Founded 2010; Farnborough, UK
HAKFLOW
UK-based cybersecurity firm specializing in blockchain security and penetration testing; provides advanced auditing and active penetration testing services to assess and improve blockchain security measures, with headquarters in London, UK.
Woodsec
UK-based cybersecurity firm specializing in penetration testing and cyber security assurance; founded 2022, with formal registration at Kidderminster, England. The company emphasizes its expertise in advanced IT support, application security, and research, serving clients with boutique, expert cybersecurity services.
KT Secure UK
KT Secure UK is a cybersecurity company based in the United Kingdom, specializing in software code signing, hardware security modules, and penetration testing services; with 2 employees, 150% YoY growth, founded in 2009, and a focus on security assessments, vulnerability testing, and key management.
Boxxe
UK-based IT solutions provider specializing in hardware, software, managed IT services, and cybersecurity; explicitly offers penetration testing (pentest) services as part of its cybersecurity portfolio; registered in England and Wales with a York headquarters.
Bae Systems
UK-based defense, security, and aerospace company headquartered in London; offers penetration testing, red teaming, and security testing services for organizations, with active cybersecurity operations and service offerings.
Securious - Data and Cyber Security
Cybersecurity compliance and pentesting company based in Exeter, UK; 11 employees with 18.2% YoY growth; founded in 2007; provides PCI DSS, ISO 27001, Cyber Essentials, and penetration testing services to UK and international clients.
Xpertex Ltd
UK-based IT services and consulting firm specializing in cybersecurity, including penetration testing and breach & attack simulation; 9 employees with -6.7% YoY growth; founded 2006; headquartered in Welwyn Garden City, England; active in security assessments, vulnerability analysis, and machine parts manufacturing.
Zepko
Cybersecurity firm based in Guildford, United Kingdom, specializing in penetration testing; offers detailed security assessments using standardized testing methodologies and emphasizes human intervention to enhance resilience.
Cybergen® Security
Cybergen® Security is a UK-based IT services and cybersecurity consulting firm founded in 2023, with a focus on penetration testing, red teaming, and threat mitigation. The company provides CREST-accredited penetration testing and 24/7 managed detection and response, emphasizing proactive security testing and vulnerability identification, despite having only 1 employee.
Protection Group International
Protection Group International is a UK-based security and investigations firm specializing in digital resilience, security consulting, and cyber security services; with 77 employees (+10.6% YoY growth), $15M annual revenue, founded in 2013 in London. PGI provides CREST-aligned penetration testing services, demonstrating formal technical standards, and serves a global client base including governments and NGOs. The company operates in multiple languages and maintains active social media engagement.
Arcanum Information Security
Cybersecurity company specializing in penetration testing and security training; 2 employees with 100% YoY growth; based in Llanegwad Ed, UK; offers external and web application pentest services, training, and media; 15,303 monthly visits, global rank #1,648,340.
Six Degrees
IT Services and Consulting company based in London, UK, with 196 employees and $157.8M annual revenue; specializes in infrastructure, hybrid cloud, Azure management, and FinOps; explicitly offers penetration testing services including Penetration Testing as a Service and Red Teaming with CHECK/CREST accreditation; founded in 2011, with $145.9M in funding and active market presence.
GoDefend (Cyber Security)
Cybersecurity company based in the United Kingdom; specializes in data security software, penetration testing, breach detection, and compliance solutions; 5 employees, founded 2018, $3.3M funding, recent £250K investment to grow threat detection tech; competes with qingteng cloud security and sonet.io.
MTI
Private UK-based IT & cybersecurity company with 214 employees, $45.6M revenue, founded in 1987; specializes in data security, data centre modernization, and IT managed services; provides penetration testing with CREST certification and active testing operations; acquired by Ricoh in 2020.
ResilientX Security
Cybersecurity company specializing in penetration testing, attack surface management, and third-party risk solutions; provides active testing and simulated attack services with a focus on web, cloud, and network security; 10 employees; Founded 2022; London, UK.
Bridewell
Cybersecurity company based in Reading, UK, specializing in computer and network security; 224 employees (+7.9% YoY growth), $6.0M revenue, founded 2013; provides penetration testing and security consulting, trusted by critical infrastructure organizations and highly regulated sectors.
CYFOR Secure | Cyber Security
Cybersecurity company based in Manchester, UK, with $4.1M annual revenue; specializes in penetration testing, digital forensics, incident response, vulnerability assessments, dark web monitoring, and cybersecurity audits; founded in 2002.
Mongoose Cyber Security
UK-based cybersecurity company specializing in CREST-accredited penetration testing; headquartered in Wilmslow, Cheshire, with official registration confirming UK operations; focuses solely on penetration testing services, emphasizing real-world threat simulation.
CyberCX
UK-based cybersecurity company providing penetration testing, incident response, vulnerability assessments, and governance, risk, and compliance services; explicitly signals UK origin and offers detailed pentest solutions.
tmc3
IT services and cybersecurity company based in the United Kingdom; 20 employees with 27.3% YoY growth; founded in 2021; specializes in penetration testing, data protection, security assurance, and secure development lifecycle for government, critical infrastructure, and healthcare sectors.
Cyberfort
UK-based cybersecurity firm specializing in penetration testing services such as code reviews, cloud security testing, AI/LLM testing, and application/web/network/internals testing; performs active attack simulations to identify vulnerabilities.
Methods
UK-based private IT & Services company specializing in digital transformation and cybersecurity; 313 employees, $148.4M revenue, founded 1990, headquartered in London, UK; provides penetration testing services with active engagements and case studies demonstrating expertise.
Wavenet
UK-based IT managed services provider specializing in cybersecurity, communications, and connectivity; offers CHECK & CREST approved penetration testing services; headquartered in Solihull, England, with multiple UK offices; focuses on enhancing security and connectivity for businesses.
Modux
UK-based cybersecurity firm specializing in penetration testing and security assessments; NCSC-approved CHECK company with government accreditation; offers security testing for IT systems, products, and services, with proven expertise in assessing security weaknesses.
Pentest Laboratories
UK-based cybersecurity company founded in 2018; specializes in penetration testing services with modernized methodologies to enhance organizational resilience against cyber threats.
CyberLegion
CyberLegion is a UK-based cybersecurity company specializing in penetration testing, secure-by-design product security, and cybersecurity advisory services; founded in 2021, it has 1 employee and offers crest-approved penetration testing, with a global rank of #6,605,571 and 385 monthly website visits.
Delta Cyber Security Ltd
UK-based cybersecurity company specializing in penetration testing, cyber essentials certification, and cloud security reviews; headquartered in Chichester, West Sussex, with a focus on simplified, accessible security solutions grounded in experience.
Testhouse
UK-based QA and security testing company headquartered in London; offers penetration testing services aligned with OWASP, PCI DSS, and GDPR, recognized by Gartner for quality assurance excellence.
ProCheckUp
ProCheckUp Ltd is a UK-based cybersecurity firm specializing in penetration testing and security audits; CREST-approved and NCSC CHECK accredited, with headquarters in Portsmouth, England, and registered at 14 St Georges Business Centre, Portsmouth, PO1 3EZ.
Acutest
UK-based software testing and quality assurance consultancy; offers penetration testing services; registered in York, England, with additional UK addresses; specializes in testing software, business processes, and IT to improve digital transformation projects.
BT Group
UK-based telecommunications company with 30,295 employees and GBP20.4B annual revenue; operates the largest fixed and mobile networks in the UK; provides active cybersecurity services including penetration testing and ethical hacking; GBP137.8M market cap; over $8.7B in funding; headquartered in London, UK.