Security Architect - Microsoft Security Platform

In this role, you design and own Colt’s Microsoft security architecture, focusing on Defender, Entra ID and Purview to modernise security posture. You will partner with Security Engineering, SOC, Risk and wider tech teams to build integrated, Zero Trust-aligned security across a hybrid estate. You’ll drive identity-driven security, data protection via Purview, and SOC enablement through Defender and Sentinel. A key hook is shaping secure, AI-enabled security capabilities with governance and least-privilege access.

• Flexible working hours
• Work from home option
• Extensive induction with mentors
• Development and educational opportunities
• Global Family Leave Policy
• Employee Assistance Program

• Act as design authority for Microsoft Security architecture (Defender, Entra ID, Purview)
• Define target architecture for Microsoft security platform aligned to Zero Trust
• Lead design/implementation of Defender across endpoints, identities, and user-facing services
• Define integration patterns between Defender and non-Microsoft security tooling across server/infrastructure
• Design/deliver Purview solutions (DLP, Information Protection, Insider Risk, data governance)
• Implement identity-first controls using Entra ID (P2) including Conditional Access, MFA, PIM
• Support SOC modernisation using Defender and Sentinel telemetry and broader data sources
• Conduct security architecture reviews and provide assurance with formal risk sign-off
• Ensure consistent deployment/operationalisation of Microsoft security at scale in a hybrid estate
• Align with regulatory requirements (TSA, DORA, ISO27001)
• Drive Secure by Design across Microsoft platforms
• Define security/governance for Microsoft Copilot/AI services and mitigate AI/LLM risks
• Engage with Microsoft and vendors on roadmap, especially XDR, data protection, AI
• Produce architecture artefacts, standards and guidance

• 5+ years in information security in large-scale enterprise or telecoms
• Deep expertise in Microsoft 365 E5 security: Defender, Entra ID, Sentinel, Purview
• Strong experience in Purview capabilities (DLP, Information Protection, Insider Risk, eDiscovery)
• Strong understanding of Zero Trust and identity-driven security
• Experience deploying Defender/SIEM within wider security ecosystem
• Experience conducting security design reviews and translating policy into controls
• Experience risk assessments using recognised methodologies
• Understanding of cloud security across Azure IaaS/PaaS/SaaS
• Ability to translate technical concepts into business outcomes
• Knowledge of Windows/AD and Linux/Unix environments
• Engineering/Computer Science degree or equivalent
• Strong teamwork and stakeholder management
• English fluency

• excellent communication
• stakeholder management
• team collaboration
• Microsoft Defender (Endpoint, Identity, Office 365, Cloud Apps)
• Microsoft Entra ID (P2), Conditional Access, identity protection
• Microsoft Sentinel