IT Systems & Infrastructure Engineer - Security

Job Location – London

Job ID – 35606

About this opportunity and L3Harris UK

Operating at 11 sites in the United Kingdom, L3Harris supports Britain's mission to secure and strengthen the country by delivering sovereign innovation across the space, air, land, sea and cyber domains. L3Harris Trenchant is an elite global team of engineers and security researchers charged with building world-class computer security products. Trenchant’s expertise is the by-product of the L3Harris acquisition of two highly-regarded information security businesses – Azimuth Security and Linchpin Labs. United under Trenchant, we are a key component of L3Harris’ Intelligence & Cyber Division. We are a trusted, discrete partner furnishing security products, consultancy, training and integration services to allied security, defence, and law enforcement agencies.

A few of our employee benefits are:

• 25 days holiday per year (plus bank holidays), increasing with long service and with the opportunity to buy/sell up to 5 days
• Private medical insurance with optional family cover
• Pension scheme of up to 8% employer contribution
• Life Assurance 4x salary (flexible up to 10x)
• Group income protection
• Flexible opt-in extras such as a health care cash plan, dental insurance, gym membership, critical illness cover, cycle to work scheme, travel insurance and electric car scheme
• Employee Family Assistance Program providing mental health and wellbeing support
• Professional membership reimbursement (discretionary)

What the role will involve

The responsibilities of your role will include the following:

• Align IT services with global standards and ensure stable, reliable infrastructure.
• Resolve issues promptly and communicate clearly for a positive user experience.
• Take ownership of problems and improve systems, processes, and service quality.
• Collaborate effectively with colleagues across regions and share knowledge.
• Enhance security and resilience through disciplined patching and monitoring.
• Build constructive, trusted relationships with the teams you support.

Technical Responsibilities

• Operate and maintain regional and global infrastructure services including servers, networks, virtualization platforms, storage systems, and cloud environments.
• Diagnose and resolve complex technical issues.
• Deploy, configure, and maintain Linux servers and containerized workloads.
• Support and improve network infrastructure, including routing, switching, firewalls, VPNs, and site-to-site connectivity.
• Automate infrastructure provisioning and management using tools such as Ansible, Terraform, Python, and Bash.
• Support cloud-based services, particularly AWS.
• Assist in the deployment and maintenance of developer tooling.
• Participate in incident response and serve as an escalation point for complex issues.
• Monitor system health and performance, using tools such as Prometheus, Grafana, and SNMP.
• Enhance infrastructure security through hardening, patching, and vulnerability remediation.

What you’ll bring

The role requires the following experience and skills:

• Proficient in Linux system administration
• Strong skills in analyzing and solving technological challenges.
• Experience with networking fundamentals, containerization technologies, and cloud platforms.
• Familiar with automation and security best practices.
• Eligibility to obtain a security clearance
• Professional experience in systems, networks, or infrastructure engineering.
• Experience supporting technical or engineering-focused teams.

Important to know

Due to the nature of our work many of our roles require a UK nationality and the ability to obtain a security clearance. Applicants who accept a conditional offer of employment must meet the requirement of right to work in the UK and must meet eligibility requirements for access to classified information and will be subject to government security checks.