Executive Summary
The Public Sector Client, part of a UK central government department, is responsible for issuing critical identity documents and safeguarding the integrity of national identity services. Operating across a distributed IT estate, the organisation faced the imperative to modernise its legacy infrastructure and align its operations with its digital transformation agenda.
The Strategic Systems Platform programme was commissioned to transition core systems into a modern, scalable, and secure digital architecture. This strategic pivot sought to enhance operational resilience, leverage hybrid cloud capabilities, and deliver services that remain sovereign and compliant with UK data residency and security policies. With increasing demands on service availability, flexibility and information assurance, Our client aimed to deliver an enterprise-grade hybrid cloud platform combining Microsoft Azure and on-premises Azure Stack Hub.
The Challenge
The programme faced complex challenges in digital transformation at scale while dealing with highly sensitive citizen data and operating under stringent security and compliance requirements. Key among these was the need to implement a hybrid cloud model that retained control over critical workloads and ensured sovereignty, all without compromising agility, cost-effectiveness, or scalability.
Previous attempts by other suppliers failed to meet the required OFFICIAL-SENSITIVE standards, particularly for air-gapped environments. Designing a hybrid architecture that met the needs of both agile delivery and traditional waterfall processes, while supporting live services and complex interdependencies, introduced operational and governance risks.
Further complexity came from needing to harmonise the requirements of multiple stakeholder groups including NCSC, GCHQ, and Microsoft while aligning with Client’s transformation roadmap. The solution had to enable iterative delivery in a secure, regulated context where collaboration across civil service and supplier teams was limited by classification protocols.
Our Solution
A&A Digital Tech was selected to design and implement a secure, sovereign hybrid cloud platform that would serve as the foundation for the Public Sector Client’s digital services transformation. Drawing on our expertise in secure cloud architectures and UK government delivery frameworks, we embedded our specialists across architecture, security governance, and delivery teams.
We architected a hybrid platform leveraging Azure Stack Hub for on-premises workloads, designed to operate disconnected from the public internet but fully integrated with the client’s broader cloud-first strategy. A&A Digital Tech collaborated with Microsoft, government security bodies, and internal client teams to develop security patterns and operational controls that met the highest standards of assurance.
Key aspects of our approach included:
🔍 Strategic discovery workshops: To establish transformation goals and assess the client’s risk posture across hybrid and air-gapped environments.
⚙️ Agile delivery methods: SCRUM ceremonies and waterfall milestone tracking to meet programme-level delivery gates, ensuring flexibility in a hybrid delivery model.
🛡️ Zero-trust architecture principles: Applied to privileged access, system deployment, and platform monitoring. Automated CI/CD pipelines (Azure DevOps, Terraform) and secure tooling (HashiCorp Vault, Splunk) were used to enforce this.
📜 Bespoke governance frameworks: Aligned with NCSC cloud security principles. Included strict segregation of duties, multi-party approval processes, and secure-by-design templates for repeatable deployment.
💻 Infrastructure as Code (IaC): Automated provisioning and configuration management reduced manual effort and errors, accelerating deployment timelines.
🤝 Collaborative engagement model: A&A Digital Tech worked across architecture, operations, and governance to ensure secure delivery, while also running capability uplift programmes (e.g., hybrid-cloud workshops, 1:1 mentoring for civil servants).
Our collaborative approach spanned technical architecture, service operations, and change management. A&A Digital Tech also ran capability uplift initiatives for civil servants, delivering technical workshops, mentoring sessions, and hybrid-cloud knowledge sharing to drive sustainable capability growth.
Outcomes
✅ Security Certification: Architecture and solution approved by NCSC, GCHQ and the Public Sector Client’s IA team for handling OFFICIAL-SENSITIVE data.
🔄 Resilience: Delivered a highly available hybrid platform with full disaster recovery capabilities.
⚡ Time-to-Value: Reduced onboarding time for secure services by 50% through pre-approved architectural patterns and automated pipelines.
💷 Cost Efficiency: Avoided capital expenditure and reduced operational cost (Millions of £s) per year through architectural innovation.
🔒 Governance Alignment: Embedded risk and compliance controls into agile delivery processes and infrastructure automation.
Key Learnings and Takeaways
🧩 Early engagement with IA, security, and vendors accelerates alignment and reduces rework.
☁️ Hybrid cloud adoption requires not only technology innovation but also tailored operating models and stakeholder engagement.
🧱 Embedding secure-by-design principles within CI/CD pipelines enhances scalability and compliance in regulated environments.
📚 Investing in civil servant upskilling ensures sustainable capability beyond contract delivery.
📦 Reusable architectural and pipeline patterns reduce time-to-deploy and increase consistency across government estates.
