Senior Network Engineer

Job description

Position Description:

At CGI, we help protect and strengthen the critical technology infrastructure that underpins the UK's defence and intelligence capabilities. As a Senior Network Engineer within our Space, Defence and Intelligence business unit, you'll take ownership of complex network environments, solve challenging technical problems and drive continuous improvements across a secure programme. Working alongside a collaborative team of experts, you'll have the autonomy to make decisions, introduce innovative solutions and enhance network performance, resilience and security. This is an opportunity to make a meaningful impact, applying your expertise to mission-critical systems while developing your career in an environment that values initiative, creativity and professional growth.

CGI was recognised in the Sunday Times Best Places to Work List 2025 and has been named a UK ‘Best Employer’ by the Financial Times. We offer a competitive salary, excellent pension, private healthcare, plus a share scheme (3.5% + 3.5% matching) which makes you a CGI Partner not just an employee. We are committed to inclusivity, building a genuinely diverse community of tech talent and inspiring everyone to pursue careers in our sector, including our Armed Forces, and are proud to hold a Gold Award in recognition of our support of the Armed Forces Corporate Covenant. Join us and you’ll be part of an open, friendly community of experts. We’ll train and support you in taking your career wherever you want it to go.

Due to the secure nature of the programme, you will need to hold UK Security Clearance or be eligible to go through this clearance. This position is based on-site in Chippenham, five days per week, due to the secure nature of the project.

Your future duties and responsibilities:

As a Senior Network Engineer, you will play a key role in maintaining, supporting and enhancing a secure, mission-critical network environment within CGI's Space, Defence and Intelligence business unit. You'll be trusted to work independently, take ownership of technical challenges and proactively identify opportunities to improve network stability, security and performance.

This role is ideal for an experienced engineer who thrives on solving complex problems, challenges existing ways of working and takes pride in delivering practical, long-term solutions. You'll have the freedom to apply your technical expertise, recommend improvements and help shape a more resilient and efficient network infrastructure, while benefiting from the knowledge and support of CGI's wider technical community.

Key responsibilities:

• Own & Resolve: Independently investigate, troubleshoot and resolve complex network issues, ensuring minimal disruption to critical services.

• Optimise & Improve: Proactively assess the existing network environment, identifying opportunities to enhance performance, resilience and operational efficiency.

• Maintain & Support: Take responsibility for the ongoing stability, availability and security of network infrastructure within a highly secure environment.

• Design & Implement: Recommend and deliver network enhancements, upgrades and configuration changes aligned with operational requirements.

• Analyse & Prevent: Identify recurring issues, conduct root cause analysis and implement sustainable solutions to prevent future incidents.

• Secure & Protect: Apply network security best practices, ensuring infrastructure remains compliant with relevant security standards and policies.

• Collaborate & Advise: Work with technical specialists, stakeholders and wider delivery teams to resolve challenges and support programme objectives.

• Document & Enhance: Maintain accurate network documentation, share technical knowledge and contribute to continuous service improvement.

Required qualifications to be successful in this role:

To succeed in this role, you'll be an experienced and proactive Senior Network Engineer with strong troubleshooting skills, a practical approach to problem-solving and the confidence to work independently in a secure technical environment. You'll be comfortable taking ownership of complex issues, identifying improvements without constant direction and delivering reliable solutions that strengthen network performance and resilience.

Essential skills and experience:

• Network Engineering Expertise: Strong experience supporting, maintaining and improving complex enterprise network environments.

• Routing & Switching: In-depth knowledge of networking technologies, including TCP/IP, VLANs, routing protocols and switching.

• Troubleshooting & Problem-Solving: Proven ability to independently diagnose and resolve complex network faults.

• Network Security: Good understanding of firewalls, network segmentation, access controls and secure networking principles.

• Continuous Improvement: Demonstrable experience identifying and implementing network improvements to enhance stability, performance and reliability.

• Technical Ownership: Ability to work autonomously, prioritise workloads and take accountability for technical outcomes.

• Infrastructure Support: Experience managing network configuration changes, upgrades, maintenance and incident resolution.

• Communication & Collaboration: Strong communication skills, with the ability to work effectively with technical teams and stakeholders.

Desirable skills and experience:

• Experience working within Defence, Government, Intelligence or other highly secure environments.

• Relevant networking certifications, such as Cisco CCNA, CCNP or equivalent.

• Experience supporting mission-critical or highly available network infrastructure.

• Familiarity with network monitoring, automation and performance optimisation tools.

• Experience working within ITIL-aligned service management environments.

Skills:

·  Firewalls
·  Linux
·  Routing/Routers
·  VMware
·  Agile
·  Communication
·  SAFe

What you can expect from us:

Together, as owners, let’s turn meaningful insights into action.

Life at CGI is rooted in ownership, teamwork, respect and belonging. Here, you’ll reach your full potential because…

You are invited to be an owner from day 1 as we work together to bring our Dream to life. That’s why we call ourselves CGI Partners rather than employees. We benefit from our collective success and actively shape our company’s strategy and direction.

Your work creates value. You’ll develop innovative solutions and build relationships with teammates and clients while accessing global capabilities to scale your ideas, embrace new opportunities, and benefit from expansive industry and technology expertise.

You’ll shape your career by joining a company built to grow and last. You’ll be supported by leaders who care about your health and well-being and provide you with opportunities to deepen your skills and broaden your horizons.

That same commitment to fairness extends to how we use technology. To support our recruitment team, AI tools may be used to help assess applications though they never replace human judgement. All hiring decisions remain entirely in the hands of our recruitment professionals.

Come join our team—one of the largest IT and business consulting services firms in the world.