Executive Summary
Our public sector client operates a large-scale national identity platform that processes and manages sensitive citizen records. In line with their digital transformation strategy, the client initiated a modernisation programme to move from legacy on-premise systems to a secure, scalable, and cost-effective public cloud environment.
This initiative was particularly critical for ensuring continued resilience and security in managing their System of Record (SoR), comprising several hundred million sensitive records, while addressing long-standing infrastructure obsolescence and inefficiencies. The client also sought to align with evolving regulatory and operational requirements around data sovereignty, security assurance, and real-time system availability.
A&A Digital Tech was selected to lead the migration strategy and architecture owing to its proven track record in secure cloud transformation, expertise in designing serverless architectures for OFFICIAL-SENSITIVE datasets, and deep experience with government-grade security standards and stakeholder governance.
The Challenge
The client faced a high-risk, highly sensitive challenge: migrating their core SoR datasets from tightly controlled, secure on-premise environments to a public cloud platform. This migration represented a significant shift in both operational mindset and technical execution.
Historically, such data remained within traditional data centres due to stringent security, sovereignty, and assurance obligations. Previous attempts by legacy suppliers had failed to gain regulatory approval due to gaps in demonstrating compliance with NCSC’s OFFICIAL-SENSITIVE controls and inability to establish trust with security stakeholders. Moreover, risk tolerance was low—any compromise could undermine national identity systems and erode public trust.
Adding to the complexity was the stakeholder environment, involving security and assurance teams, delivery managers, legal advisors, regulators, and technology suppliers. Disagreements about architecture models, access controls, and data classification norms caused significant delays and friction.
Further, the migration landscape was technically intricate: 800+ million records, downstream system dependencies, and a multi-supplier delivery model requiring agile co-ordination, robust governance, and fail-safe rollback mechanisms. It wasn’t enough to move the data which meant that the solution had to demonstrably uphold the highest levels of availability, auditability, and regulatory compliance while enabling future scalability.
This initiative required more than technical acumen. It demanded a deep understanding of public sector governance, stakeholder management, and innovation in secure-by-design cloud architecture. There was a need to challenge long-standing norms while ensuring no compromise to security or operational continuity.
Our Approach and Solution
A&A Digital Tech’s approach was anchored in secure-by-design cloud principles, stakeholder co-creation, and DevSecOps. The programme was executed in three parallel tracks i.e., Security Architecture, Agile Delivery, and Stakeholder Consensus.
Security Architecture & Zero Trust Platform:
We designed a serverless, zero-trust architecture using AWS-native services, avoiding EC2 to reduce attack vectors. Technologies included S3, Lambda, API Gateway, DynamoDB, RDS, Kinesis, and Secrets Manager. Encryption-at-rest and in-transit was implemented via client-managed KMS keys. Network isolation was achieved through private endpoints and strict IAM controls. CI/CD pipelines enforced security gates, SAST/CVE scans, and automated rollback strategies.
Privileged Access & Monitoring:
A multi-party approval mechanism governed privileged access, while real-time protective monitoring was enabled using StreamAlert integrated with Slack and PagerDuty. A&A Digital Tech developed “Lockdown Lambdas” to isolate the environment autonomously during suspected breaches, an innovation later adopted across other services.
Stakeholder Engagement & Regulatory Alignment:
A&A Digital Tech facilitated architecture walkthroughs with regulators, Information Assurance leads, and platform owners. Concerns were mitigated through demonstrable compliance with NCSC’s 14 Cloud Security Principles. Our team co-authored assurance artefacts and evidence packs that won full endorsement from independent security auditors.
Agile, Transparent Delivery:
Delivery was phased using SCRUM sprints. Artifacts were managed in JIRA and Confluence with fortnightly ‘Show and Tell’ demos. Convergent delivery pipelines supported versioning, rollback, and monitoring. Civil servants were embedded within squads to ensure capability uplift and facilitate knowledge transfer.
This platform became the organisation’s first approved public cloud deployment for OFFICIAL-SENSITIVE data, establishing reusable patterns for wider government adoption.
Outcomes
🔒 Security Accreditation: First NCSC-endorsed OFFICIAL-SENSITIVE serverless deployment in AWS.
💷 Cost Savings: Millions of GBP saved annually through decommissioning of legacy on-prem infrastructure.
⚙️ Performance & Scalability: Query performance improved by 300%, with elastic infrastructure supporting 10x data throughput.
📜 Compliance: Full alignment with GDPR, Data Protection Act 2018, and NCSC cloud guidelines.
🎓 Civil Servant Upskilling: Government staff trained in AWS, GraphQL, and agile methodologies throughout delivery lifecycle.
Key Learnings and Takeaways
🛡️ Security-by-Design is Foundational: Embedding security into every layer of cloud architecture is key to unlocking public sector trust in digital solutions.
🏛️ Regulatory Engagement is Essential: Early and ongoing collaboration with authorities like NCSC and GCHQ accelerates design approval and stakeholder confidence.
🔁 Agile + DevSecOps Enables Resilience: Combining agile ways of working with automated security and deployment pipelines ensures compliance doesn’t slow delivery.
🤝 Uplift Through Embedded Collaboration: Embedding civil servants in squads fosters capability building and ensures continuity after delivery.
📦 Reusable Patterns = Scalable Impact: The architectural and security patterns developed are now reusable across government—amplifying their strategic value.
