Client challenge: HMRC wanted to migrate its Operational Data Store (ODS) from on-premises data centres to modern, cloud-native architecture while ensuring uninterrupted service delivery for critical government services.

Solution: HMRC and Capgemini migrated the ODS to the cloud in one weekend, uniting 40+ multi supplier and delivery teams for a seamless, secure transition.

Benefits:

  • Faster and more reliable services
  • Reduced operational risk and technical debt
  • Better alignment with government digital ambitions and strategy

HM Revenue & Customs (HMRC) partnered with Capgemini to migrate its critical Operational Data Store (ODS) from on-premises data centres to a scalable, secure, cloud platform over a single weekend, ensuring uninterrupted services for key UK tax services. This complex migration involved over 40 teams, six suppliers, moved 13 billion records with more than 70 connected services, and represented a major step in HMRC’s digital transformation while aligning with the government ambitions for digital-first tax administration by 2029-2030.

Delivering uninterrupted service through collaboration

HMRC has a vital purpose: collecting the money that funds public services. To ensure that it can fulfil this essential role, the department is modernising its operations. In this way, it intends to transform the UK’s tax and customs system into a digital-first organisation, with no less than 90% of interactions undertaken digitally by 2029-2030.

In alignment with government ambitions, the department’s Digital Transformation Roadmap includes integrating AI, expanding self-service options, and simplifying tax processes to reduce friction for compliant taxpayers. For HMRC, modernising existing operational services requires the replacement of legacy systems and platforms with cloud-based alternatives.  

HMRC’s ODS supports public-facing data such as VAT, Self Assessment, and Corporation Tax. Transitioning ODS from physical servers to the cloud was key for HMRC to help the department in its journey to improve day-to-day performance and the customer experience; closing the tax gap; and modernising the tax and customs system.

Originally conceived to act as a shared operational data store and centralised source for operational tax data, ODS has 119 interfaces looked after by over 40 different teams. It provides a persistent data repository, delivering secure and consistent real-time or near-real-time data sources for immediate operational use.

Given the significance of ODS, it was necessary to minimise any disruption to those who rely on the data it provides. Therefore, robust planning and testing was critical to ensure the delivery of the migration within a single weekend.

HMRC partnered with Capgemini to navigate a complex landscape of delivery teams and a multi-supplier environment, ensuring a seamless transition from legacy to cloud.

Navigating a complex multi-supplier environment

The ODS modernisation project enabled HMRC to migrate the service to a new, cloud-based database as a service and leverage evergreen capabilities, meaning the platform stays modern and supported over time, with continuous improvements rather than periodic major upgrades.

Over one weekend, 13 billion records and more than 70 connected services were moved to the cloud. Careful planning, a phased go-live and dedicated support meant issues were handled quickly and with operational stability maintained.

By aligning HMRC’s stringent regulatory and operational standards while embracing Capgemini’s One Team approach, the project team unified over 40 delivery teams, six suppliers, and approximately 250 people into a single, collaborative unit. This enabled the joint team to prepare and accelerate the delivery of a detailed Cutover and Migration Plan, which in turn helped deliver the migration within a set timeframe. Preparation included:  

  • DevSecOps practices and automation tools – implemented to embed security into the project from the start and at every stage of development using continuous integration/continuous deployment (CI/CD) pipelines. This helped to reduce risk and ensure high quality, aligning with HMRC’s enterprise patterns 1.
  • Extensive testing conducted across all environments – five end-to-end “dress rehearsals” refined timings, addressed scheduling issues, and ensured mitigation plans were in place and agreed upon with live support teams.

Building a cloud-based and future-ready solution

The migration, focused on platform modernisation and service continuity, was seamlessly executed over the implementation weekend without interrupting the functionality of services for users.

As a result of its collaboration with Capgemini, the migration has enabled HMRC to deliver faster, more reliable support to customers, reduce technical debt, enhance performance and improve availability of services and data access.

This reflects the strategic shift toward modern, agile, and secure services that can be delivered faster, more reliably, and with enhanced system performance, stability, and security.

This migration lays the foundations for future innovation in data-driven policy and creates opportunities to leverage future innovations in AI, automation, and policy integration.

1 HMRC’s enterprise patterns – a set of standardised architectural and engineering practices used by the department to guide the development, deployment, and operation of digital services and platforms.