Principal Site Reliability Engineer x5 (SC Cleared) South England - hybrid working - £70,000 - £90,000 + perm benefits We are seeking experienced Principal Site Reliability Engineers (SRE) to join a high-performing engineering team delivering resilient, cloud-native platforms for UK-based customers. These roles blend senior technical leadership with hands-on delivery, covering both project-based work and the ongoing reliability, scalability, and security of critical services. You'll work closely with other senior engineers in small, collaborative teams, taking ownership of platform reliability, setting best practices, and mentoring others. The role supports critical national infrastructure, requires participation in an on-call rota, and operates within a hybrid working model across UK offices, client sites, and home. Key responsibilities Design, build, and maintain highly available, scalable, and resilient platforms, prioritising standardisation, reuse, and automation Champion GitOps-first approaches, minimising manual configuration ("ClickOps") Lead and contribute to Site Reliability Engineering practices, including error budgets, SLOs, SLIs, and incident management Work in agile delivery teams, aligning engineering outcomes to customer and service reliability goals Operate within defined on-call rotas, supporting services underpinning critical national infrastructure Pro...