Senior Principal - P&C Platform Engineer

Business Introduction
GSK remains committed to achieving bold commercial ambitions for the future. By 2031, we aim to deliver £40 billion in annual sales, leveraging our existing strong performance momentum to significantly increase our positive impact on the health of billions of patients globally. Our Ahead Together strategy is centred on early intervention to prevent and alter the course of disease, thereby protecting people and supporting healthcare systems.
Our diverse portfolio consists of vaccines, specialty medicines, and general medicines.
Through continuous innovation and a dedicated focus on scientific and technical excellence, we strive to develop and launch new, groundbreaking treatments that address critical health challenges.
Job Purpose
Build, automate and run the platform that 50,000+ employees across [X] countries use to communicate and collaborate — Microsoft Teams, SharePoint Online and OneDrive, Exchange Online, the Microsoft 365 apps, Power Platform and Microsoft 365 Copilot.
This is the hands-on build role. The Platform Engineer takes architecture direction and a prioritised backlog and turns them into working, tested, automated, documented configuration in production. The expectation is engineering rather than administration: configuration expressed as code and deployed through pipelines, not clicked through a portal and remembered by whoever was on shift.
The role also runs what it builds. Platform Engineers own the operational health of their workloads — diagnosing the awkward, intermittent, only-happens-in-Tokyo problems that never reproduce in a lab, and eliminating the root cause rather than closing the ticket.
Key Responsibilities
Design, build, test and deploy configuration across the Microsoft 365 estate: Teams policies, SharePoint and OneDrive settings, Exchange Online transport and mail flow, Purview policies, Entra ID groups and Conditional Access as it applies to collaboration workloads.
Implement to the reference architecture and standards set by the Principal Architect; raise a design challenge when reality does not match the design rather than quietly deviating.
Deliver backlog items from sprint to production with the tests, telemetry, documentation and rollback path included — "done" means running and observable, not merely configured.
Build and maintain integrations using Microsoft Graph and platform APIs; write the connective tissue between M365, ServiceNow, HR systems and the wider application estate.
Automate everything that would otherwise be done twice. Provisioning, lifecycle, reporting, remediation, joiner/mover/leaver flows, licence assignment and reclamation.
Express tenant configuration as code in version control; build and maintain CI/CD pipelines for policy and solution deployment with automated validation and staged ring-based rollout.
Replace manual runbook steps with self-healing and self-service; treat a recurring manual task as a defect with a backlog item attached.
Own operational health of assigned workloads: monitoring, alerting, capacity, service health response and performance.
Investigate and resolve complex incidents and problems — third-line escalation for collaboration platform issues — and drive permanent root-cause elimination.
Participate in an on-call rotation for major incidents affecting the collaboration platform.
Manage the continuous change stream from Microsoft: assess message centre and roadmap items, test in a lab tenant, and implement, defer or disable with the reasoning recorded.
Maintain patch, currency and configuration compliance; remediate vulnerabilities and drift.
Implement and maintain security and information governance controls in the collaboration estate: sensitivity labels, DLP, retention, external sharing controls, app consent and Conditional Access.
Produce the evidence that audits require — configuration baselines, change records, access reviews — generated automatically wherever possible.
Build to regulated-environment requirements where applicable, including GxP-validated systems and the qualification and change control they demand.
Work daily with the Product Owner on refinement and estimation, and with the Architect on design; give honest estimates and flag risk early.
Produce operational documentation, runbooks and knowledge articles good enough that the service desk can use them and the next engineer can pick the work up.
Support and coach the service desk and second-line teams; reduce escalation volume by transferring capability, not by absorbing it.
Mentor junior engineers and contribute to engineering standards and code review within the squad.
Education & Professional Qualifications
Bachelor's degree in Computer Science, Engineering or a related discipline, or equivalent demonstrable professional experience. Strong practical experience is an acceptable substitute for formal qualification.
Relevant certifications desirable (e.g., Microsoft 365 Certified: Administrator Expert, Teams Administrator Associate, Identity and Access Administrator Associate, Information Protection and Compliance Administrator, Power Platform Solution Architect, Azure Administrator, ITIL v4 Foundation).
Area of Specialisation
Hands-on Microsoft 365 platform engineering across the core collaboration workloads — Exchange Online, SharePoint Online / OneDrive and Microsoft Teams — at 50,000-user scale.
Configuration-as-code for tenant settings — Git, CI/CD pipelines, automated validation and staged ring-based rollout — plus advanced PowerShell and Microsoft Graph automation.
Microsoft Purview implementation — sensitivity labels, DLP, retention — and the practical behaviour of external sharing, Conditional Access and app consent controls once real users meet them.
Complex collaboration-platform troubleshooting across client, identity, network and service layers, with root-cause elimination rather than ticket closure.
Experience Required
15Years overall and 10+ years in IT engineering or platform operations, including 5+ years working hands-on with Microsoft 365 in a production enterprise environment.
Experience supporting or engineering a tenant of 5,000+ users; comfortable with the difference between a small tenant and a large one.
Demonstrable hands-on capability across at least two of Exchange Online, SharePoint Online/OneDrive, or Microsoft Teams — at a level that includes troubleshooting, not only configuration.
Working PowerShell proficiency with real examples of automation delivered into production, plus practical experience calling the Microsoft Graph API.
Familiarity with Git and pull-request-based working; willingness to work configuration-as-code if not already doing so.
Experience operating in an ITIL-aligned change and incident process, including production change ownership.
Experience delivering within a Scrum or Kanban squad, including refinement, estimation and sprint commitment.
Willingness to participate in an on-call rotation for major incidents.
Fluent English, written and spoken; able to explain a technical issue to a non-technical colleague.
Desirable:
Experience in a regulated industry — pharmaceutical, life sciences, biotech, financial services or healthcare — including GxP/CSV/CSA and validated-system change control.
Migration delivery at scale — on-premises Exchange or SharePoint to cloud, file share to OneDrive/SharePoint, tenant-to-tenant, or third-party platform (Slack, Zoom, Google Workspace, Box) consolidation.
Teams Phone / voice — Direct Routing, Operator Connect, PSTN migration.
Teams Rooms and collaboration hardware — deployment, configuration and remote management at estate scale.
Viva suite implementation — Connections, Engage, Learning, Insights.
Power Platform development — Power Automate flows, Power Apps, Dataverse, Copilot Studio agents.
A second language beyond PowerShell — Python, C# or Go — and experience building small services or Azure Functions.
Infrastructure-as-code tooling — Bicep, ARM or Terraform for the Azure resources supporting the platform.
Endpoint management adjacency — Intune, device compliance and the endpoint's role in Conditional Access.
Security engineering exposure — Defender for Office 365, Defender for Cloud Apps, threat hunting in M365 audit data.
Accessibility testing and remediation in collaboration tooling.
Skills/Background
Deep hands-on configuration and troubleshooting across the core M365 workloads — Exchange Online (mail flow, transport rules, hybrid, anti-spam), SharePoint Online and OneDrive (site and permission models, sharing controls, migration), and Microsoft Teams (policies, lifecycle, meetings, channels).
Entra ID as it applies to collaboration — groups and dynamic membership, Conditional Access, app registrations and consent, service principals and app-only authentication.
Microsoft Purview implementation — sensitivity labels, DLP policies, retention and disposition — and the practical behaviour of each once real users meet it.
Microsoft 365 apps deployment and configuration — servicing channels, policy management via the Cloud Policy service, add-in management.
Power Platform administration — environments, DLP co