Senior Cyber Security Engineer

Salary: £64,005 for Manchester and £66,332 for London. In addition, there will be opportunities to qualify for additional allowances and a skills-related payment under the Government Digital and Data Profession Capability Framework (GDDPCF).

Flexible working: We support full‑time, part‑time, compressed hours, and other flexible working patterns. We recognise the importance of achieving a positive work-home balance and will work with colleagues to consider flexible working arrangements where possible, taking individual circumstances and business needs into account. Some homeworking opportunities may be available; however, this role is primarily office-based due to the sensitive nature of the work, and home working is not guaranteed.

About us: MI5 keeps the country safe from serious threats like terrorism and attempts by states to harm the UK, its people and way of life. We carry out investigations by obtaining, analysing, and assessing intelligence, and then work with a range of partners including MI6 and GCHQ to disrupt these threats. Through our protective security arm, we provide advice and guidance to government, businesses and other organisations about how to keep themselves safe. A role in MI5 means you’ll do unique and challenging work in a supportive and encouraging environment, making a real difference to UK national security.

The role: As a Senior Cyber Security Engineer, you’ll play a central role in protecting the organisation’s digital products, embedding security into how systems are designed and built. The role combines engineering and security expertise, applying practical skills to identify weaknesses, validate controls and help teams deliver secure, resilient systems from the outset. Working within a highly collaborative environment, you’ll contribute to organisation-wide security capability, tackling complex challenges across a diverse and evolving technology landscape. Early engagement in the development lifecycle is vital, shaping design decisions, influencing architecture and ensuring security is integrated into modern engineering practices. This role combines technical depth with real influence. Threat modelling, vulnerability assessment and security testing form a core part of the work, applying an adversarial mindset to uncover risks. Just as important is working directly with engineers, architects and stakeholders to resolve those risks, improve practices and raise the organisation’s overall security maturity. You’ll take a "purple team" approach, combining elements of red team testing and defensive security – identifying vulnerabilities and working with teams to fix them, building better, more secure systems. The role also extends to the wider direction of security engineering: supporting less experienced colleagues, influencing technical decisions and helping stakeholders understand risk, trade-offs and priorities. With a high degree of autonomy, you’ll take ownership of complex problems and play a key role in how security is delivered across the organisation.

About you: You’ll bring practical experience in a security-focused role, such as cyber security engineering, penetration testing or a closely related technical discipline. This could be supported by a STEM degree with relevant experience, or a technical role with a strong security focus. Experience with real-world systems is essential, identifying and solving security issues, alongside a solid understanding of core security principles such as Secure by Design. You’ll have applied techniques such as threat modelling, vulnerability assessment or security testing, and be confident thinking critically about how systems can be exploited and secured. You communicate clearly with both technical and non-technical stakeholders and are comfortable working collaboratively to resolve issues. Curious and pragmatic, you’re motivated to keep learning and apply your expertise to complex, high-impact challenges.

Training and development: From the moment you join, you’ll be supported to develop your expertise in cyber security through a blend of hands-on experience and structured learning. You’ll work closely with experienced colleagues across a range of security challenges, gaining exposure to different systems, tools and approaches. A wide range of development opportunities is available, including on-demand learning platforms, virtual cyber ranges and formal training aligned to your role. There is also support available to achieve industry-recognised certifications, such as SANS (The Sans Institute), GIAC (Global Information Assurance Certification), CISSP (Certified Information Systems Security Professional Qualification) or Offensive Security qualifications, alongside opportunities to attend UK-based and international security conferences. As you grow in the role, you’ll take on increasingly detailed work, building both technical depth and influence, with the support of your team, mentoring opportunities and exposure to real-world threat intelligence.

Rewards and benefits: You’ll receive a starting salary from £64,005 to £66,332, depending on location, plus other benefits including: 25 Days Annual Leave automatically rising to 30 days after 5 years’ service, and an additional 10.5 days public and privilege holidays, opportunities to be recognised through our employee performance scheme, dedicated development budget, interest-free season ticket loan, cycle to work scheme, facilities such as a gym, restaurant, and on-site coffee bars (at some locations), paid parental and adoption leave.

Equal opportunities: At MI5 diversity and inclusion are critical to our mission. To protect the UK, we need a truly diverse workforce that reflects the society we serve. This includes diversity in every sense of the word: those with different backgrounds, ages, ethnicities, gender identities, sexual orientations, ways of thinking and those with disabilities or neurodivergent conditions. We therefore welcome and encourage applications from everyone, including those from groups that are under-represented in our workforce such as women, those from an ethnic minority background, people with disabilities and those from low socio-economic backgrounds.

We’re Disability Confident: MI5 is proud to have achieved Leader status within the Department for Work and Pensions Disability Confident scheme. This is aimed at encouraging employers to think differently about disability and take action to improve how they recruit, retain, and develop disabled people. Being Disability Confident, we aim to offer a fair and proportionate number of person-to-person interviews to any candidate who self-identifies as disabled and meets the essential criteria for the role.

To secure an interview for this vacancy, the essential criteria (in order of application process) are: You'll be required to reach the minimum pass mark for the online Situational Judgement Test (SJT), which assesses criteria important for all roles in our organisation, demonstrate practical familiarity in a security-focused role – to be assessed at application sift, demonstrate the ability to identify and solve real-world security issues including applying threat modelling, vulnerability assessment, or security testing, and a solid understanding of Secure by Design principles – to be assessed at application sift.

There is a wide range of extra support available throughout the recruitment process to enable you to do your best. Before you apply: To work at MI5, you need to be a British citizen or hold dual British nationality. This role requires the highest security clearance, known as Developed Vetting (DV). Please note we have a strict drugs policy, so once you start your application, you can’t take any recreational drugs and you’ll need to declare your previous drug usage at the relevant stage. The role is based in London or Greater Manchester so you’ll need to live within a commutable distance. We offer reasonable reimbursement of travel costs for candidates attending in‑person appointments during the recruitment and vetting process. Full details will be provided with your interview or assessment invitation. Please note, you should only launch your application from within the UK. If you are based overseas, you should wait until you visit the UK to launch an application. You should not discuss your application, other than with your partner or a close family member.