Electoral registration statistics, UK QMI

• Statistical designation: accredited official statistics
• Data collection: administrative data
• Frequency: annual
• How compiled: aggregation of electoral register data supplied by local authorities
• Geographic coverage: UK, country, region, local authority, Westminster parliamentary constituency
• Last revised: 2 April 2026
• Related publications: Electoral registration statistics for the UK (dataset)

This quality and methodology report contains information on the quality characteristics of the data (including the European Statistical System five dimensions of quality) as well as the methods used to create it.

The information in this report will help you to:

• understand the strengths and limitations of the data
• learn about existing uses and users of the data
• understand the methods used to create the data
• help you to decide suitable uses for the data
• reduce the risk of misusing data

• Electoral registration statistics are accredited official statistics that have been independently reviewed by the Office for Statistics Regulation (OSR) and confirmed to comply with the standards of trustworthiness, quality and value in the Code of Practice for Statistics.

• They are published for the UK, its constituent countries, English regions, local government areas and Westminster parliamentary constituencies (those used to elect members to the UK Parliament in Westminster).

• They usually provide annual counts of the number of people who are registered on electoral rolls on 1 December each year, but do not provide details on the personal characteristics of the electorate, nor the size of the population eligible to vote.

• Electoral registration statistics are used by boundary commissions, the Electoral Commission and central government to help with the improvement of electoral policies and for statutory reviews of Parliamentary constituency and local electoral boundaries.

• Since the December 2020 publication, electoral registration statistics for Wales have not included all registered voters; this is because they have not reflected changes to eligibility for local government and Senedd elections, specifically the reduction of the minimum voting age to 16 years, and more extensive voting rights for overseas nationals.

• Data quality issues meant there was no December 2024 edition of the dataset, and the December 2025 edition was limited to statistics for Westminster parliamentary constituencies; we have been working to resolve these issues and expect to return to a full publication for the December 2026 edition (for further information, see Section 4: Quality summary, under the Recent changes to electoral law and quality impacts on publication subheading.

Overview

Electoral registration statistics for the UK are usually published annually in April. They provide statistics for local authorities and Westminster parliamentary constituencies. These have differing rules on who can register to vote; we discuss this further in Section 5: Quality characteristics of the data, under the Concepts and definitions subheading.

The statistics cover the number of people who were registered to vote after the annual canvass in each local authority (LA), which informs the LAs' annual published electoral registers. By law, LAs must publish their registers by 1 December each year, except for LAs where an election is held between 1 July and 1 December, in which case the publication of the register can be delayed until up to 1 February the following year. This means that, although our annual publication routinely refers to December, in any one year there may be a small number of LAs who supply us with statistics that have a slightly later reference point.

The publication also includes the number of "attainers" on the electoral registers. These are people who have not yet reached voting age but will do so before the next expected publication of the full register.

The Office for National Statistics' (ONS's) publication covers the entire UK, incorporating information supplied by National Records of Scotland (NRS) and the Electoral Office for Northern Ireland (EONI) for their respective countries.

Recent changes to electoral law and quality impacts on publication

In 2021, the franchise for elections to Welsh local authorities was extended to reduce the minimum voting age to 16 years and to extend the voting rights of foreign nationals. This was done to align with the voting age for elections to the Welsh Parliament (Senedd).

However, these new groups of voters were not included in the December 2021 edition of the electoral registration statistics and were only available for 6 of the 22 local authorities in Wales (Cardiff, Denbighshire, Flintshire, Monmouthshire, Newport and Wrexham) for the December 2022 and December 2023 editions.

In 2024, the franchise for local government elections in England also changed, reducing the number of EU citizens who were eligible to vote. Because the software systems available to LAs to supply the data to the ONS had not all been updated to take account of both this and the changes in the remaining 16 local authorities in Wales, it was decided not to publish a December 2024 edition.

Although efforts to update the systems progressed during 2025, they were not all updated in time for the December 2025 collection. In response, the ONS liaised with important data users and agreed that it would publish December 2025 statistics for Westminster parliamentary constituencies only, which were unaffected by the legislative changes at local level. Although this has resulted in a reduced scope, it ensures that the data that users can access is of good quality; it was also seen as preferable to either delaying the publication substantially, not publishing at all, or publishing incomplete LA-level data.

Work to update the supply systems has continued and, as at March 2026, was nearing completion. It is the ONS's intention that the December 2026 edition will once again include statistics for local authorities, fully reflecting legislative changes.

Uses and users

The main users of the data are the boundary commissions (who specify the boundaries used for elections), the Electoral Commission and central government, particularly the Ministry of Housing, Communities and Local Government (MHCLG). They are also used by Members of Parliament (MPs) and the general public.

Strengths and limitations

The main strengths of these electoral registration statistics for the UK are that:

• they represent the most accurate count available of the number of electors on 1 December, based on the information supplied by each local authority
• they are usually published annually in April, four months after the reference date
• since 2001, they have been derived using data supplied on a usual reference date of 1 December, and the methodology has remained consistent

The main limitations of these electoral registration statistics are that:

• they provide counts of those registered but do not provide an estimate of the population eligible to register
• they do not include any information about the age or sex of electors
• changes to eligibility for local government elections in Wales in 2021 are only partially reflected in our subsequent publications, which therefore do not provide full counts of the electorate for local elections in Wales and elections to the Welsh Parliament
• the absence of LA statistics from the December 2025 edition means that users may have to rely on their estimates of LA numbers, or on figures from earlier publications
• they are not an estimate of the number of people resident in the area; for that, our population estimates should be used

These statistics are not an estimate of the number of people resident in an area because:

• not everyone is eligible to register to vote

• not everyone who is eligible to register does so

• some people who split their time between two areas (such as students) may register in two areas, although they may only vote in one area in any one election

• overseas British voters (who are allowed to vote in Westminster parliamentary elections) will not actually live in the area; however, they must register in the local authority where they were last registered to vote or where they were last resident before they left the UK

• some double counting in electoral registers occurs because of the time taken to remove people from the registers after they have moved away from an area; similarly, people may still appear on the register for a while after they have died

This section provides a range of information that describes the quality and characteristics of Electoral registration statistics and identifies issues that should be noted with these data.

Relevance

Relevance is the degree to which statistical outputs meet users' needs.

The main use of the data is to inform changes to the boundaries of local authorities and their subdivisions, and of parliamentary constituencies. An important aspect of this is seeking to ensure that councillors in each local authority represent similar numbers of electors, with the same principle applying to MPs in Parliament.

We collate and publish electoral registration statistics, which are used by central government departments (such as the Ministry of Housing, Communities and Local Government (MHCLG)) and the Electoral Commission, and by boundary commissions when they review boundaries. Other users include MPs and the general public.

The statistics meet user needs in terms of coverage and detail (except in years where there is not a full publication). The format and details to be collected on the "Summary of Register of Electors" (the form supplied by the Electoral Registration Officer (ERO) in each local authority) are specified by the main users. We also ensure that the latest statutory boundaries, codes and names for geographic areas are used.

Accuracy and reliability

This is the degree of closeness between an estimate and the true value.

Electoral registration statistics represent the most accurate count available of the number of electors on 1 December, based on the information provided on the "Summary of Register of Electors" by the EROs for each local authority. For England and Wales, we follow up missing or incomplete returns.

If no return is received prior to publication, data from the most recent available year are used instead, and a note in the dataset identifies these areas to users.

There are no statistical quality measures, such as standard errors, relating to the accuracy of electoral registration statistics, as the statistics are aggregated counts and no estimation is involved. The main threats to the accuracy of the statistics are non-response and clerical error associated with the data supply from each local authority, and processing error when the statistics are compiled. Quality checks and procedures, such as consistency checks on calculations, are in place to minimise these threats.

Corrections to errors with published electoral registration statistics have occasionally been necessary in the past. These corrections were released promptly and in an open and transparent manner and users were alerted in line with The Office for National Statistics' Revisions Policy and Correction of Errors Policy. Any future revisions and corrections would also follow these policies.

Although the data we publish reflect what is recorded in the electoral registers, the registers themselves are known to contain inaccurate entries. The Electoral Commission's 2023 report: Electoral registers in the UK indicates that the most common error that would affect the quality of our statistics occurs where a person who no longer lives at an address remains on the electoral register at that address.

Coherence and comparability

Coherence is the degree to which data that are derived from different sources or methods, but refer to the same topic, are similar. Comparability is the degree to which data can be compared over time and domain, for example, geographic level.

Since 2001, electoral registration statistics have usually been based on a reference date of 1 December, and the methodology has remained consistent. Prior to 2001, the reference date for the electoral registration statistics was 16 February.

There have also been some instances since 2001 where different reference dates have been used. The most recent was when, because of the December 2019 General Election, EROs variously published their electoral registers between November 2019 and March 2020. However, this meant that the Office for National Statistics's (ONS's) publication did not cover the full electorate who had registered by the time of the election. Therefore, in addition to its December 2019 edition, the ONS published a March 2020 edition.

Although the standard reference date for the statistics is 1 December, LAs may delay the publication of their electoral register up until 1 February if they have an election between 1 July and 1 December. This means that there may be slight time differences between LAs in terms of the actual reference date of the statistics.

Various factors can affect the proportion of people registered at any point in time. These are:

• proximity to elections; there is often a peak in registrations in the period before elections

• from 2014, Individual Electoral Registration (IER) was introduced, replacing the previous household-based registration system; this allowed individuals more control over the registration process and increased accuracy

These will affect year-on-year comparisons, as will changes in the electorate as a result of legislation, such as the changes in minimum voting age and rules around which nationalities may register. Changes to local authority and parliamentary boundaries (described in Section 5: Quality characteristics of the data under the Geography subheading) will also affect comparisons.

There is also some double counting of the registered electorate, resulting from the time taken to remove people from the registers after they have moved away from an area. Similarly, people may still appear on the register for a while after they have died. The impact of these factors is likely to differ between areas because different local authorities may make the required updates over different periods of time.

Accessibility and clarity

Accessibility is the ease with which users can access the data, also reflecting the format in which the data are available and the availability of supporting information. Clarity refers to the quality and sufficiency of the release details, illustrations and accompanying advice.

Electoral registration statistics from 2000 onwards are available in our Electoral registration statistics for the UK dataset. Local authority statistics for 1998 and 1999 are also available on that page. Other statistics for 1997 to 1999 are available on request by emailing pop.info@ons.gov.uk. Some data are also available for the period 1991 to 1996 and further information on these are also available on request.

The Office for National Statistics (ONS) release calendar provides the release date and location of each new set of statistics, which can be downloaded in Microsoft Excel format. The Excel files also contain user information, including advice on where geographic changes have occurred. From 2011 to 2021, the statistics were also accompanied by a statistical bulletin. Since 2022, we have published data without commentary.

Most queries can be answered from the website datasets. Any additional enquiries regarding electoral registration statistics can be made via email at pop.info@ons.gov.uk or telephone +44 1329 444661.

General information regarding conditions of access to data:

• Terms and conditions (for data on our website)
• Copyright and re-use of published data
• Accessibility

Timeliness and punctuality

Timeliness refers to the lapse of time between publication and the period to which the data refer. Punctuality refers to the gap between planned and actual publication dates.

Electoral registration statistics for the UK are usually published annually in April, four months after the reference date. This time lag reflects the availability of data in the form of a completed response from the local authority, and the time taken to process the data and compile the statistics. The aim is for the statistics to be available within the timescale required by the boundary commissions to allow for their use in boundary reviews.

In previous years, the planned publication date on the release calendar has always been met. However, in the unlikely event of a change to the release schedule, an announcement will be made at least two weeks in advance, as set out in the Code of Practice for Statistics. In the unlikely event of a change to the pre-announced release schedule, public attention will be drawn to the change and the reasons for the change will be explained fully at the same time.

Concepts and definitions (including list of changes to definitions)

Concepts and definitions describe the legislation governing the output and a description of the classifications used in the output.

Electoral registration statistics refer to the number of people who were registered to vote if an election had been held on 1 December of the reference year. This is the current reference date for electoral registers. Prior to 2001, the annual canvass resulted in registers that came into effect on 16 February.

Different types of elections have different franchises (meaning the groups of people who are allowed to vote). This publication provides data on the number of people registered who may vote in Westminster parliamentary constituency and local government elections, respectively, as well as regional and national totals.

Westminster parliamentary elections have consistent rules across the UK, whereas local government elections vary by country. The rules are complex and have changed over time. The House of Commons Library's 2026 publication, Who can vote in UK elections? provides more detail. However, some fundamental aspects of the current position are that:

• there are consistent rules across the UK for elections to the UK Parliament in Westminster

• rules vary across the UK for local elections, including elections to devolved parliaments

• one major aspect of variation is the minimum age at which people are allowed to vote; this is 16 years for local authority elections in Scotland and Wales, and also elections to the Scottish Parliament and Welsh Parliament (Senedd), but is 18 years across the UK for elections to the UK Parliament, and is also 18 years for local authority elections in England and Northern Ireland

• the other major aspect of variation is in the nationalities that are allowed to vote; in general, British, Irish and qualifying Commonwealth citizens may vote in any election, however, the other nationalities that may vote varies by type of election and across the UK

Geography

Over time, both local authorities and Westminster parliamentary constituencies may be subject to boundary change or more extensive restructuring.

At the time of the December 2025 edition of the statistics, the Westminster parliamentary constituencies reflect those introduced for the General Election in 2024. The next review of boundaries is expected to start in 2029 and must be completed by 2031. A look-up between the previous and new boundaries is available.

The December 2025 edition does not include statistics for local authorities (the most recent data available are in the December 2023 edition). However, information on changes since 2009 is available in the Register of Geographic Codes.

Responsibility for compiling electoral registers lies with individual local authorities (LAs). In England and Wales, the Office for National Statistics (ONS) requests data on the numbers of electors as at 1 December of the reference year from the electoral registration officer (ERO) of each LA. The EROs email the information to us on forms known as RPF29s.

The raw data counts from the RPF29s are quality assured, and unusual or unexpected figures are queried with the ERO before the data are used in the compilation of the statistics. The counts of electors and attainers are aggregated to produce electoral registration statistics for the required geographies.

Missing or incomplete returns are followed up by the ONS. If no return is received before publication, data from the last available year are usually used. A footnote against the published table identifies these areas to users.

National Records of Scotland (NRS) and the Electoral Office for Northern Ireland (EONI) follow similar procedures to the ONS for their respective countries, and supply the data to the ONS for publication of the UK statistics.

Statistical disclosure control

Statistical disclosure control methodology is not necessary as the counts of electors at local authority and Parliamentary constituency level are large enough to ensure that information attributable to an individual cannot be identified in the published outputs.

Assessment of user needs and perceptions

We engage regularly with the main user of electoral registration statistics, including the Ministry of Housing, Communities and Local Government (MHCLG), the Electoral Commission and boundary commissions.

Local area users are consulted through the Central and Local Information Partnership (CLIP) Population Subgroup. The aim of the group is to improve communication between the Office for National Statistics (ONS) and some users of population statistics produced by the ONS.