Microsoft 365 Security Architect: Zero Trust & AI Security

Colt Technology Services; Greater London; Hybrid; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Flexible working hours

Mentor program and induction

Educational opportunities

Global Family Leave Policy

Employee Assistance Program

Inclusion networks

Job summary

Colt Technology Services is seeking a Security Architect specialising in the Microsoft Security platform (M365 E5) to join the Security and Resilience – Security Architecture team.

You will act as the design authority for Microsoft Defender, Entra ID and Purview, driving Zero Trust-aligned security architectures across Colt's estate and collaborating with Security Engineering, SOC, Risk and wider technology teams.

Qualifications

• 5+ years in information security within large-scale enterprise or telecommunications environments.
• Deep expertise in Microsoft 365 E5 security capabilities, including Defender, Entra ID, Sentinel and Purview.
• Strong understanding of Zero Trust architecture principles, particularly identity-driven security models.
• Experience deploying and operating Defender and SIEM capabilities.
• Experience conducting security design reviews and translating policy into practical controls.
• Experience performing risk assessments aligned to recognised methodologies.
• Strong understanding of cloud security concepts across IaaS, PaaS and SaaS, particularly within Azure environments.
• Ability to translate complex technical security concepts into clear business-aligned outcomes.
• Good understanding of networking and enterprise platforms (Windows/Active Directory, Linux/Unix environments).
• Engineering/Computer Science degree or equivalent practical experience.
• Strong team player with the ability to lead initiatives across multiple stakeholders.
• Excellent communication and stakeholder management skills.
• Understanding of security risks associated with AI/LLM technologies, including prompt injection, data leakage and over-permissioning risks.
• Fluent in English (technical and non-technical communication).

Responsibilities

• Act as the design authority for Microsoft Security architecture, covering Defender, Entra ID and Purview capabilities.
• Define and maintain the target architecture for the Microsoft security platform, aligned to Colt’s Zero Trust strategy.
• Lead the design and implementation of Microsoft Defender capabilities across endpoints, identities and user-facing services.
• Define appropriate integration patterns between Microsoft Defender and non-Microsoft security tooling across server and infrastructure environments.
• Design and deliver Microsoft Purview solutions, including DLP, Information Protection, Insider Risk and data governance.
• Define and implement identity-first security controls using Entra ID (P2), including Conditional Access, MFA and Privileged Identity Management (PIM).
• Support the modernisation of Colt’s SOC operating model, leveraging Defender and Sentinel for telemetry and data sources.
• Conduct security architecture reviews and provide assurance for solutions leveraging Microsoft security technologies.
• Ensure consistent deployment and operationalisation of Microsoft security capabilities at scale across a hybrid estate.
• Drive adoption of Secure by Design principles across Microsoft-based platforms and solutions.
• Define and implement security and governance controls for Microsoft Copilot and AI/LLM services, ensuring enterprise data is protected.
• Assess and mitigate risks associated with AI/LLM usage, including prompt injection and data leakage.
• Ensure AI-enabled services follow Zero Trust, enforcing least-privilege access to enterprise data.
• Engage with Microsoft and vendors to stay aligned with capabilities and roadmaps.
• Produce high-quality architecture artefacts, standards and guidance documentation.

Skills

Microsoft 365 E5 security

Zero Trust

Defender capabilities

SIEM integration

Azure cloud security

Security architecture

Stakeholder management

Communication

Education

Engineering/Computer Science degree

Tools

Microsoft Defender

Entra ID

Purview

Sentinel

Job description

Colt Technology Services is seeking a Security Architect specialising in the Microsoft Security platform (M365 E5) to join the Security and Resilience – Security Architecture team.

You will act as the design authority for Microsoft Defender, Entra ID and Purview, driving Zero Trust-aligned security architectures across Colt's estate and collaborating with Security Engineering, SOC, Risk and wider technology teams.