Security Architect - Entra ID/MS/Azure

Overview

As Security Architect, you will lead security architecture for a major transformation programme, embedding security across identity, endpoints, M365, applications, and networks. You will balance security with delivery, guiding risk-based decisions and ensuring controls are practical during coexistence and target-state transitions. You’ll articulate security principles and provide independent assurance of designs and migration approaches. The role is on-site in London with a 50/50 hybrid option and offers a meaningful chance to shape secure, future-ready services for the public sector.

Pay / Benefits

• Autonomy to develop and grow
• Impactful project work contributing to society
• Strong leadership and collaborative environment
• LinkedIn Learning and management development
• Flexible working (home/part-time)
• 25 days annual leave + bank holidays + option to buy 5 days

Responsibilities

• Establish and maintain security architecture principles, patterns, standards and control requirements for the programme
• Define security design-assurance criteria and assess technical designs against requirements
• Assess threats, risks, vulnerabilities and control gaps across current, coexistence, transition and target states
• Develop proportionate security controls for secure coexistence between existing and new services
• Define and assure Zero Trust principles across identity, devices, applications, data and network access
• Collaborate with identity and directory architecture to secure authentication and administrative controls
• Define security requirements for endpoint, email, data, applications and networks
• Establish monitoring, logging, threat detection and incident response requirements
• Review designs to identify security weaknesses and remediation needs
• Assess migration strategies from a security perspective and document residual risk and treatments
• Maintain visibility of significant security risks and owner accountability
• Provide security input into programme plans, designs, testing and handover
• Support security testing and assurance activities prior to migrations or go-live
• Align designs with security policies, standards, data protection obligations and regulatory requirements
• Produce and maintain security architecture documentation (HLDs, threat models, risk assessments, etc.)
• Offer risk-based security recommendations to leadership and stakeholders
• Drive continuous improvement of security controls as the transformation progresses

Key requirements

• Extensive experience as Security Architect in complex enterprise environments
• Strong knowledge of Microsoft Entra ID, Microsoft 365, Azure, endpoint security, networks and application security
• Understanding of hybrid and cloud security architectures and legacy transition challenges
• Proven application of Zero Trust, least privilege, privileged access and defence-in-depth principles
• Identity and access security expertise including authentication, Conditional Access and administrative controls
• Experience designing security controls for endpoints, email, data, applications, infrastructure and networks
• Strong logging, monitoring, threat detection and incident-response knowledge
• Threat modelling, risk assessment, control mapping and architecture assurance experience
• Experience assessing security risks in migration, coexistence and cutover
• Understanding of data protection, information governance and regulatory requirements
• Ability to translate technical risks into clear business impacts and recommendations
• Strong technical writing skills for architecture documentation

• Pragmatic security professional who balances risk with delivery
• Strong communication with senior stakeholders
• Collaborative, able to challenge designs constructively
• Microsoft Entra ID
• Microsoft 365
• Azure

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