Security Architect - Microsoft Security Platform

Colt provides network, voice and data centre services to thousands of businesses around the world, allowing them to focus on delivering their business goals instead of the underlying infrastructure.

Why we need this role

We are looking for a Security Architect specialising in the Microsoft Security platform (M365 E5) to join the Security and Resilience – Security Architecture team.

This role acts as the design authority and subject matter expert for Microsoft security technologies, including Defender, Entra ID and Purview, and will play a key role in modernising Colt’s security posture.

The successful candidate will work closely with Security Engineering, SOC, Threat Intelligence and Risk functions, as well as wider technology teams (DIO, Network Engineering, Service Delivery), to design and implement integrated, Zero Trust-aligned security architectures across the Colt estate.

The role combines:

• Deep technical ownership of the Microsoft Security stack (E5)
• Security design, architecture and assurance
• Strategic transformation across Colt technology domains

You will play a critical role in driving:

• Identity-driven and endpoint-focused security architecture for user-facing environments
• Data protection and compliance capabilities through Microsoft Purview
• Modern SOC enablement leveraging Defender and Sentinel telemetry alongside broader tooling
• The secure adoption of Microsoft Copilot and AI/LLM-driven capabilities, ensuring appropriate governance, data protection and access controls

What you will do

• 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, ensuring integration with wider security tooling where required
• Define appropriate integration patterns between Microsoft Defender and non-Microsoft security tooling, particularly across server and infrastructure environments
• Design and deliver Microsoft Purview solutions, including Data Loss Prevention (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 user and endpoint telemetry, alongside integration of broader infrastructure data sources
• Conduct security architecture reviews and provide assurance for solutions leveraging Microsoft security technologies, including defining requirements and supporting formal sign-off or risk acceptance
• Ensure consistent deployment and operationalisation of Microsoft security capabilities at scale, across a complex, hybrid estate
• Ensure alignment with regulatory requirements such as TSA, DORA and ISO27001
• 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 appropriately protected
• Assess and mitigate risks associated with AI/LLM usage, including prompt injection, data leakage, over-permissioned access and unintended data exposure
• Ensure AI-enabled services follow Zero Trust principles, enforcing least-privilege access to enterprise data accessed by Copilot and related tools
• Engage with Microsoft and other vendors to stay aligned with emerging capabilities and roadmap developments, particularly across XDR, data protection and AI
• Produce high-quality architecture artefacts, standards and guidance documentation

What we're looking for

Must haves:

• 5+ years of experience in information security within large-scale enterprise or telecommunications environments 
• Deep expertise in Microsoft 365 E5 security capabilities, including: 
• Microsoft Defender (Endpoint, Identity, Office 365, Cloud Apps)
• Microsoft Entra ID (P2), Conditional Access and identity protection
• Microsoft Sentinel (SIEM integration)
• Microsoft Purview
• Strong experience designing and implementing Microsoft Purview capabilities, including DLP, Information Protection, Insider Risk and eDiscovery 
• Strong understanding of Zero Trust architecture principles, particularly identity-driven security models 
• Experience deploying and operating Defender and SIEM capabilities, integrated within a wider security ecosystem 
• 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 (e.g. Microsoft Copilot) 
• Fluent in English (technical and non-technical communication)

Might haves:

• Experience designing and implementing security and governance controls for AI/LLM platforms, including Microsoft Copilot integrated with Microsoft Purview 
• Experience consolidating endpoint and SaaS security capabilities into the Microsoft Defender ecosystem 
• Experience with Security Copilot and security automation 
• Understanding of Telecoms Security Act (TSA) requirements and implementation approaches 
• Experience working in regulated environments (telecommunications, financial services, critical infrastructure)

What we offer you:

Looking to make a mark?

At Colt, you’ll make a difference. Because around here, we empower people. We don’t tell you what to do.

Instead, we employ people we trust, who come together across the globe to create intelligent solutions.

Our global teams are full of ambitious, driven people, all working together towards one shared purpose: to put the power of the digital universe in the hands of our customers wherever, whenever and however they want.

We give our people the opportunity to inspire and lead teams, and work on projects that connect people, cities, businesses, and ideas. We want you to help us change the world, for the better.

Diversity and inclusion

• Inclusion and valuing diversity of thought and experience are at the heart of our culture here at Colt. From day one, you’ll be encouraged to be yourself because we believe that’s what helps our people to thrive. We welcome people with diverse backgrounds and experiences, regardless of their gender identity or expression, sexual orientation, race, religion, disability, neurodiversity, age, marital status, pregnancy status, or place of birth.

Most recently we have:

• Signed the UN Women Empowerment Principles which guide our Gender Action Plan
• Trained 60 (and growing) Colties to be Mental Health First Aiders
• Please speak with a member of our recruitment team if you require adjustments to our recruitment process to support you. For more information about our Inclusion and Diversity agenda, visit our DEI pages .

Benefits

Our benefits support you through all parts of life, for both physical and mental health.

• Flexible working hours and the option to work from home.
• Extensive induction program with experienced mentors and buddies.
• Opportunities for further development and educational opportunities.
• Global Family Leave Policy.
• Employee Assistance Program.
• Internal inclusion & diversity employee networks.

A global network

• When you join Colt you become part of our global network. We are proud of our colleagues and the stories and experience they bring – take a look at ‘Our People’ site including our Empowered Women in Tech.