Posted on 2025/12/11
Senior Penetration Tester (CTL / CSTL) | CHECK | Remote (UK)
Optimal
United Kingdom
Full Description
Senior Penetration Tester (CTL / CSTL) | CHECK | Remote (UK) | 20% Travel
Location: United Kingdom (Fully Remote) - Travel across the UK (approx. 20%), fully expensed
Package: £80,000 – £100,000 base salary + Excellent Benefits
Eligibility: Must hold UK residency + valid SC Clearance and CHECK certification (CTL or CSTL)
Travel: Role includes up to 15/20% UK travel to client sites across The UK (all expenses covered)
🚨 Please only apply if you have ALL the following 🚨
• 6+ years’ hands-on penetration testing experience
• Current CTL or CSTL status (held for 2+ years)
• Active SC Clearance
• CHECK certification (CTL / CSTL / CSTM - you must hold CHECK status, we will verify)
• Strong track record delivering advanced pen testing across infrastructure and/or applications
• Ability to work independently in senior-level client-facing environments
• Willingness to travel approximately 15/20% across the UK
Required Background
• 6+ years’ industry experience in offensive security / penetration testing
• Demonstrable depth in at least one of the following:
• Infrastructure Pen Testing
• Application / Web App Pen Testing
• Strong knowledge of modern attack techniques, tooling, and methodologies
• Experience delivering reports, presenting findings, and advising on remediation
• Exposure to large-scale enterprise, government, or regulated environments
• Ability to run complex engagements end-to-end with minimal oversight
• Clear understanding of threat modelling, risk assessment, and senior stakeholder communication
ℹ️ Very Important Notes
• You MUST hold CTL or CSTL status (CHECK-approved)
• You MUST hold SC Clearance
• This is a senior, hands-on role - not suitable for juniors or mid-level testers
• The role includes UK-wide travel (approx. 20%), fully expensed
• Dual-skilled CTLs (Infrastructure + Apps) will be considered for the top salary band
• Strong communication and client-facing professionalism is essential
Must-Haves (Non – negotiable)
• CTL or CSTL status held for minimum 2 years
• CHECK registration (CTL / CSTL / CSTM — must confirm you hold CHECK status)
• Deep technical proficiency in offensive security
• Ability to scope, plan, execute, and deliver high-quality testing engagements
• Strong reporting, documentation, and advisory capabilities
• Experience working with enterprise or government clients
• SC Cleared
• UK-based and eligible to work & travel freely
• Stable career history and proven delivery of long-term engagements
Bonus Experience
• Dual-skilled CTL (Infrastructure + Applications)
• Experience mentoring or guiding junior testers
• Red Teaming exposure
• Experience with tooling and automation for testing
• Knowledge of cloud security (AWS/Azure)
• Threat intelligence or purple team collaboration experience
Hands-On Experience With
• Infrastructure penetration testing
• Web and application penetration testing
• Advanced exploitation, enumeration, and privilege escalation
• Reporting to CHECK standards
• Vulnerability assessment tooling
• Manual testing methodologies aligned to industry best practice
• Working with clients across public sector, enterprise, or highly regulated industries
What You’ll Be Doing
Pen Testing & Delivery
• Deliver high-quality penetration testing engagements (infrastructure, applications, cloud etc.)
• Execute senior-level testing aligned to CHECK requirements
• Provide in-depth, quality reporting with remediation guidance
• Lead or contribute to multi-scope testing assignments
Quality & Ownership
• Ensure testing is delivered to the highest technical and professional standard
• Maintain CHECK-level methodologies and best practices
• Support continuous improvement in offensive security approaches
Client Interaction
• Present findings and recommendations to technical and non-technical stakeholders
• Work directly with engineering, security, and leadership teams
• Provide expert guidance, advisory support, and risk insight
If you meet all the above essentials and are a highly capable Senior Penetration Tester with CTL/CSTL and SC, get in touch for an immediate conversation.

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