Salary: £70,000 - 84,500 per year Requirements: We require proven experience providing technical guidance and infrastructure administration at a senior level. We require sole British nationality due to the nature of our projects. We require eligibility to obtain and maintain UK Government security clearance. We require domain experience within the defence or high-security infrastructure sector. We require comprehensive knowledge of VMware vSphere 8.0 or above and Fibre Channel storage technologies. We require strong capability with Microsoft OS 2019 and 2022, Exchange, Office 365, and Active Directory Federated trusts. We require experience with Citrix XenApp, XenDesktop, and Citrix Netscaler. We require technical capability with cloud environments such as Amazon Web Services or Azure. We require practical knowledge of Linux environments and Ansible automation tools. We require familiarity with SQL Server administration and project frameworks including ITIL, Agile, or Scrum. Responsibilities: We will have the successful candidate act as the systems administration lead on advanced projects and major programmes. We will have the successful candidate install, configure, administer, and troubleshoot complex infrastructure and application deployments. We will expect the successful candidate to apply subject matter expertise to provide technical recommendations to management and guide team members. We will have the successful candidate participate in a technical roster to support resilient services and manage planned infrastructure changes. We will expect the successful candidate to maintain and disseminate approved operational procedures aligned with industry security standards. We will have the successful candidate take ownership of core infrastructure design and technical guidance within a critical sector. We will have the successful candidate collaborate with senior management to deliver robust technical research and influence engineering practices. Technologies: Active Directory Ansible Azure Citrix Cloud Support ITIL Linux Office 365 SQL Security VMware Web More: We are offering a permanent Principal Systems Administrator role based in Cheltenham with a hybrid working pattern. Our package includes a performance-related annual cash bonus, up to 8% employer pension contribution via salary exchange, comprehensive private medical and dental insurance, an optional compressed working schedule with every other Friday off, 25 days annual leave with the option to buy or sell leave, a workplace nursery scheme with a monthly employer contribution, support for industry memberships, and unlimited access to global online learning platforms. The role requires travel within the United Kingdom up to 25% of the time, with occasional international travel to regional offices. We operate in a critical, high-security environment where structural stability, resilient infrastructure, and long-term career progression are valued, and we will represent the successful candidate through each stage of the process with support from a specialist technical recruiter. last updated 24 week of 2026