Executive Summary
Our client, a central UK government department, is a regulated data provider operating in a high-security environment with classification levels extending up to SECRET/TOP SECRET. Operating nationwide and interfacing with over 80 other government departments, the organisation’s strategic priority was to modernise their legacy infrastructure while meeting stringent regulatory, data classification, and sovereignty requirements. Considering growing demand for scalable, secure, and cloud-native infrastructure solutions that did not compromise on national data sovereignty, the department aimed to explore the feasibility of hybrid cloud technology, particularly Microsoft Azure Stack Hub, hosted within their own secure data centres. A&A Digital Tech was selected as a trusted delivery partner based on our proven capabilities in regulated environments, deep architectural expertise, and strong relationships with Microsoft and public sector cybersecurity bodies.
The Challenge
The client faced a complex and high-stakes challenge: modernise their critical infrastructure for regulated workloads without compromising data sovereignty, system security, or operational continuity. The business and technical problems were multifaceted. Their existing systems were tightly coupled with legacy infrastructure often proprietary, on-premises, and not suited to the agile development and rapid release cycles demanded by modern digital services. This limited their ability to scale or integrate with emerging technologies and exposed operational risks due to aging hardware and vendor lock-ins.
Furthermore, due to the classification levels involved conventional public cloud solutions were non-viable. There was an urgent requirement to find an approach that would uphold the National Cyber Security Centre (NCSC) cloud security principles, align with data classification governance, and deliver secure, performant, and cost-effective services. Initial internal attempts to explore private cloud options had faltered due to the complexity of compliance requirements, lack of familiarity with hybrid solutions, and the absence of a holistic architecture and implementation roadmap. With interdependent deliverables spanning multiple government programmes and suppliers, a strategic, multi-disciplinary partner was crucial to de-risk and deliver transformation within challenging timelines.
Our Approach and Solution
A&A Digital Tech’s response was tailored through deep domain knowledge, agile execution frameworks, and collaborative architecture-led delivery. We began with a discovery and diagnostic phase involving detailed stakeholder interviews, security assessments, and infrastructure audits. A pilot initiative was designed to test Microsoft Azure Stack Hub in a disconnected, sovereign mode an approach never previously validated at this scale for regulated workloads within the department.
A&A Digital Tech’s architects developed the Options proposal, High-Level and Low-Level Design (HLD/LLD) artefacts for a hybrid deployment model that met both security and data residency requirements. We incorporated defence-in-depth architecture patterns and implemented Zero Trust principles, privilege access controls via Azure DevOps and Active Directory integration, and secure CI/CD pipelines with end-to-end encryption. Our team worked closely with NCSC, Microsoft, and internal department stakeholders to align the architecture to security policies.
From procurement and hardware configuration to the build-out of an operational environment supporting air-gapped and internet-connected workloads, A&A Digital Tech ensured end-to-end ownership. We built standardised server images, deployed governance frameworks for continuous compliance, and introduced automated monitoring and incident response. The change was enabled with minimal disruption to operational workloads, and A&A Digital Tech’s technical authors produced high-quality documentation, while knowledge transfer activities ensured in-house civil servants were upskilled throughout the engagement.
The engagement epitomised A&A Digital Tech’s proactive ethos. We coordinated across multiple stakeholders, resolved conflicts between waterfall and agile dependencies, and brought forward innovative ideas such as multi-step privilege escalation and self-healing infrastructure models. Our engineering and delivery disciplines ensured each milestone was met despite complex dependencies, with a clear focus on long-term maintainability and operational sovereignty.
Outcomes
🛡️ Enabled Sovereign Cloud Hosting
Successfully deployed Azure Stack Hub in a disconnected, on-premise mode to host workloads for higher classification.
🔐 Security Excellence
Designed and implemented Zero Trust security patterns endorsed by NCSC and aligned with department’s security protocols.
💰 Cost Efficiency
Achieved capital expenditure savings and operational cost savings in millions through hybrid cloud innovation and infrastructure rationalisation.
⚙️ Operational Continuity
Delivered infrastructure transformation without any disruption to business-as-usual or classified operational systems.
📘 Knowledge Uplift
Enabled civil service teams with structured KT plans, technical documentation, and shadowing sessions to ensure post-transition autonomy and support readiness.
Key Learnings & Takeaways
🤝 Strategic Alignment Matters
Early engagement and co-design with NCSC, Department’s TDA, and Microsoft expedited approvals and reduced delivery risk.
🚀 Innovation with Assurance
Successfully piloting Azure Stack Hub with layered security controls created a blueprint now referenced across government.
🔁 Agile in Regulated Environments
Agile delivery can be embedded even in high-security contexts, provided it is adapted to regulatory and organisational constraints.
🔄 Cross-Vendor Collaboration is Key
Strong coordination between stakeholders, suppliers, and governance boards was essential to align dependencies and de-risk delivery.
📈 Value Beyond Technology
Beyond infrastructure, the project uplifted digital maturity, operational capability, and internal cloud adoption strategies across the client’s organisation.
