Over the coming years, 134 councils will consolidate into 38 new authorities, affecting more than 15 million residents across England.
Elections are expected to take place in May 2027, with most of the new councils formally assuming responsibility for services on 1 April 2028.
This is not only a significant structural change but also one of the largest local government data and technology transformation challenges undertaken in decades.
Under current local government reorganisation plans, many two-tier council areas will be replaced by new unitary authorities. From vesting day, the new organisations will assume responsibility for services previously managed across multiple councils. Staff, systems, processes, and millions of records will need to transition to the new authorities.
Council merger discussions usually focus on governance, leadership structures and political accountability. Yet the success of these new authorities will depend on something far less visible: their data.
Behind every council merger are hundreds of systems and millions of records. Each council may have its own council tax, benefits, housing, licensing, social care and case management platforms, developed at different times and configured around different processes.
Bringing organisations together means bringing all this information together too. Years of independent system investment can create data silos across departments and councils. Unless these silos are addressed as part of the merger programme, they can increase operational risk, reduce service efficiency and limit future AI capabilities.
When data is fragmented, duplicated or inconsistent, the consequences extend far beyond IT. Effective data governance in local government is essential to overcoming these challenges. Without agreed standards, ownership and accountability, merged authorities risk inheriting the same data issues they are trying to eliminate.
One resident might appear in several systems under slightly different records. One address could be held in three different formats. Separate teams may have their own versions of the same information, with no clear way to determine which is correct.
For residents, that could mean repeating their story to multiple teams or waiting longer for a straightforward answer. For employees, it could mean spending valuable time identifying duplicate records, resolving discrepancies and determining which information can be trusted.
Data issues can delay critical services and increase operational and regulatory risk. For councils supporting vulnerable residents, accurate and accessible safeguarding records are fundamental to service continuity.
Greater system connectivity can also increase shared exposure to cyber risk. In November 2025, a cyber incident affected shared IT systems and services used by three London councils. Because their systems were connected, the impact extended across the authorities. As councils come together through reorganisation, cyber security and resilience need to be built into the programme from day one.
The lesson for merging authorities is not that systems should remain disconnected. It is that cyber security, access controls, resilience and information governance must be designed into the programme from the outset.
Data readiness must be a core merger workstream
Vesting day is the point at which a new council formally assumes responsibility for services, assets, staff and operations. For most authorities involved in the current reorganisation programme, the Government intends that elections take place on 6 May 2027, ahead of the vesting day on 1 April 2028. Surrey is following an earlier timetable, with its new councils expected to vest on 1 April 2027.
On vesting day, the new authority must be able to operate safely and legally. It does not need to have completed every aspect of its transformation, but its essential services must continue.
A seamless digital experience remains an important goal, but it does not need to be fully realised on day one. Trying to redesign every service and replace every system before vesting day could introduce unnecessary complexity.
Data readiness must therefore be treated as a core transformation workstream, not simply as a technology exercise. Councils need to understand which systems contain critical information, how data will be transferred and accessed, who will be accountable for it and how its quality and security will be maintained. These decisions need to shape the programme from the beginning.
Council mergers are not only a challenge. They also create a rare opportunity to address long-standing data issues and establish the foundations for future innovation.
For many councils, merger programmes provide an opportunity to review AI governance, data governance and information management practices at the same time. Establishing clear frameworks can help ensure future AI initiatives are secure, compliant and built on trusted data.
AI in local government continues to attract significant attention because of its potential to improve efficiency, enhance services and support better decision-making. Research published by the Tony Blair Institute for Global Change estimates that AI could generate productivity gains worth £8 billion a year across local government in England and Wales, equivalent to approximately £325 per household. The figure represents an estimate of potential productivity value rather than a guaranteed cash saving.
However, AI is only as effective as the data it relies upon. Imagine three councils merging. Each has a different case management system, separate processes, and potentially a different definition of what a 'case' is.
One authority may organise information around a resident, while another structures it around a household, property or service request.
Without consistent definitions and records, AI cannot reliably identify patterns or support better decisions.
The same challenge applies to properties, suppliers, services and locations. If the underlying information is incomplete, duplicated or incorrectly matched, AI could reinforce existing problems rather than solve them.
Conversely, councils that use their merger programmes to standardise, cleanse and govern their data will be in a much stronger position to realise AI's potential. Strong data foundations not only support a successful merger. They can also improve AI readiness across the new authority. In many cases, the work required for a successful merger is the same work required for successful AI adoption.
“AI is often seen as the destination, but for local government, the real opportunity starts with data. Council mergers give authorities a rare chance to address long-standing data challenges and create foundations that support operational resilience, better services and future innovation.”
Ian Bobbett, Chief Data Officer, Crimson
Somerset Council provides a practical example of the data consolidation required during local government reorganisation. The unitary authority was created on 1 April 2023, bringing together Somerset County Council and the four former district councils of Mendip, Sedgemoor, Somerset West and Taunton, and South Somerset.
As part of the transition, four Local Land and Property Gazetteers and five Local Street Gazetteer datasets had to be consolidated into a single system. The programme had six months to complete the work before vesting day.
The records varied in completeness and format, so the work involved cleansing and aligning the data rather than simply moving it between systems. The resulting dataset achieved Gold Standard data quality under GeoPlace's annual Improvement Schedule.
Data migration is not simply a transfer exercise. Combining datasets without resolving inconsistencies moves existing problems into the new organisation, while standardisation creates a stronger foundation for day-one services.
Somerset's wider technology programme also involved bringing together five different IT environments, including 7,000 user accounts, multiple Microsoft 365 workloads and several Active Directory domains. The scale of this work illustrates why councils need to begin planning well before vesting day.
Although April 2028 may feel distant, large-scale data transformation programmes require careful planning and execution. Councils should already be assessing their application landscape, identifying critical datasets, defining governance models and establishing clear ownership across the future organisation.
They need a complete view of the applications and data sources used across the merging authorities. This includes understanding where information is duplicated, where local government data silos exist and which records are essential for day-one services. Councils must also determine which systems will be retained, consolidated, replaced or retired, as well as where processes and data definitions differ.
A data maturity assessment for local government can help identify gaps in data quality, governance, ownership, accessibility and reporting before migration begins. It can also provide a baseline from which the future authority can prioritise investment, develop its data strategy and measure progress.
Delaying these activities increases cost, complexity and risk. Starting early provides an opportunity to simplify the migration, protect service continuity, and establish stronger foundations for the new authority. Councils that leave it too late risk spending years correcting inherited problems after the new organisation has gone live.
These priorities must align with the council's future operating model, service priorities, and transformation roadmap. Delivery requires collaboration among service leaders, data specialists, technology teams, information governance professionals, and frontline employees.
At Crimson, we help public sector organisations turn data and technology into better outcomes for residents, employees and communities.
Our specialists support councils in establishing robust data foundations, modernising legacy platforms, adopting cloud technologies and preparing for AI-enabled services. Through data governance programmes, AI readiness assessments, and data maturity assessments for local government, we help councils understand whether their data is accurate, accessible, secure, and ready to support transformation.
This helps authorities establish a clear view of their current environment, identify priority risks and develop a practical roadmap that supports both day-one continuity and longer-term improvement.
Crimson recently supported Merton Council in migrating a legacy system to Microsoft Azure, improving platform resilience and enabling remote access for employees. Although a council merger is significantly larger in scale, the same principles apply: understand the existing environment, reduce reliance on ageing technology, and create a trusted foundation for future services.
Council mergers present a unique opportunity to reshape how services are delivered. The decisions made today will determine whether new authorities inherit long-standing data challenges or gain the foundations for a more connected, efficient and intelligent future.
The merger may be mandated. The success of the transformation is not.
Book a meeting with Will Jones, Industry Practice Director for Local and Regional Government at Crimson