Principal Security EngineerOur client, a leading global supplier for IT services, requires Principal Security Engineer to be based at their client''s office in London, UK.This is a hybrid role - you can work remotely in the UK and attend the London office 4 days per week .This is a 6+ month temporary contract to start ASAPDay rate: Competitive Market rateSenior hands-on secure engineer responsible for secure-by-design and operational security across the programme. Validate every delivery activity from a cyber security perspective - from threat model at requirements capture, through architecture and design approval, build assurance, security testing, live validation, hyper-care, and operational handover to BAU and external assurance. The principal authority on threat modelling, control validation, and security evidence across the CIS Controls v8.1 IG3 scope.Key ResponsibilitiesOperate as senior cyber architect and SME within the programme''s structured operating model - actively engaged from requirements capture through to BAU handover, owning Definition-of-Done evidence at every gate.Break down each Master Programme Plan activity into discrete People/Process/Technology tasks viewed through a cyber security lens - define the validation and assurance criteria, embed them as DoD acceptance criteria, and evidence them before status can advance.Requirements: author threat model v1, control intent statement, and compensating controls; validate requirements against current operation