Electoral statistics, UK: 2017

• The total number of UK Parliamentary electors increased by 380,000 (0.8%) between December 2016 and December 2017, a smaller increase than in the previous year.

• The total number of UK local government electors increased by more than half a million (1.2%) between December 2016 and December 2017.

• Of the 650 Parliamentary constituencies in the UK, 480 (74%) had an increase in Parliamentary electors between December 2016 and December 2017.

• The number of Parliamentary and local government electors increased across all four countries of the UK.

• Following a reduction of 3% in the number of electors between December 2015 and December 2016, the electorate in Northern Ireland increased by 3% in the year to December 2017.

“In the year to December 2017, the number of people registered to vote in Parliamentary elections across the UK increased by around 400,000. This follows an increase of around 1 million the previous year. The number of registered Parliamentary electors currently stands at its highest level since 2012 and is at least partly driven by there being either a general election or referendum in each of the past three years.“

Neil Park, Population Statistics Division, Office for National Statistics

Electoral statistics are available for the two main groups of voters:

• Parliamentary electors – those entitled to vote in Westminster Parliamentary elections

• local government electors – those entitled to vote in local government elections

The difference in who is entitled to vote at Parliamentary and/or local elections depends largely on residence and citizenship conditions. Local government electors, for example, include those European Union citizens resident in the UK who are not entitled to vote in Westminster Parliamentary elections, whilst Parliamentary electors include British citizens resident overseas who are not entitled to vote in local government elections.

The majority of those registered to vote in local government elections are also eligible to vote in European elections. To be entitled to vote in European elections in the UK, European Union (EU) citizens are required to request the right to vote in this country rather than their home country. Those persons who do not make this request will not be included in the European Parliament electorate. The local government electorate in Scotland includes 16- and 17-year-olds who are ineligible to vote in European elections. Further information on who can vote in different UK elections can be found on the GOV.UK website.

There are three main reasons why the registered numbers of electors in an area can change from year to year:

• a change in the size of the population who are entitled to vote; for example, due to international migration, internal migration, deaths

• a change in the proportion of the eligible population who actually register to vote; for example, more people registering as a result of better canvassing or due to an election

• changes to the franchise in Scotland in the summer of 2015 to allow 16- and 17-year-olds to vote in Scottish Parliamentary elections and local government elections in Scotland

For England and Wales, electoral statistics are taken from data supplied to Office for National Statistics by local Electoral Registration Officers. Data for Scotland are similarly collected by National Records of Scotland (NRS). Data for Northern Ireland are collected by the Electoral Office for Northern Ireland (EONI). We collate these statistics for the UK using the data supplied by NRS and EONI.

The electoral statistics we publish 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 boundaries. The statistics are also of interest to Members of Parliament and the general public.

Electoral statistics represent the most accurate count possible of the number of people on electoral registers each year. They are subject to full quality assurance procedures and are reliable and provide comparable data across the UK constituent countries. Information on the quality of these statistics is provided in the Quality and Methodology Information report.

The total number of UK Parliamentary electors in December 2017 was 46,148,000, an increase of 380,000 (0.8%) from December 2016.

The total number of Parliamentary electors in each of the UK constituent countries and the percentage changes between 2016 and 2017 was:

• England – 38,693,900, an increase of 0.8%

• Wales – 2,261,200, an increase of 0.8%

• Scotland – 3,950,600, an increase of 0.5%

• Northern Ireland – 1,242,300, an increase of 3.0%

Figure 1 shows the different patterns of change in Parliamentary electors between the UK constituent countries over the last seven years. Between December 2016 and December 2017, the number of electors increased in all four countries.

In the year to December 2017, the Parliamentary electors in Northern Ireland increased by 3%; this follows a decrease of 3% in the year to December 2016. The decrease in the number of Parliamentary electors in Northern Ireland between 2015 and 2016 can be explained partly by the removal of 60,000 people from the electoral register who had failed to update their details following the 2013 canvass of electors (PDF, 30KB). Between December 2016 and December 2017, the number of Parliamentary electors in Northern Ireland increased by 3%; this reflects that there were both general and Northern Ireland Assembly elections in 2017 and that prior to the Assembly elections in March 2017 there was a public awareness campaign encouraging people to make sure they were registered (PDF, 76KB).

The number of electors in England and Wales increased by 0.8% in the year to December 2017. This was a lower rate of increase than seen in the previous year (2.6% in England, 2.8% in Wales). The number of electors in Scotland increased by 0.5% in the year to December 2017, a slightly lower rate of increase than the previous year (0.8%).

There are at present 650 Westminster Parliamentary constituencies in the UK, made up of 533 in England, 59 in Scotland, 40 in Wales and 18 in Northern Ireland. These boundaries came into effect at the May 2010 General Election. The typical size of constituencies differs between the constituent countries of the UK. In 2017, the median total Parliamentary electorate across constituencies was about 56,000 in Wales, 68,300 in Northern Ireland, 67,200 in Scotland and 72,200 in England.

The Parliamentary constituency with the smallest-sized electorate in 2017 was Na h-Eileanan an Iar, at 21,200 and the largest electorate at 109,900 was the Isle of Wight. The same pattern was seen in 2016. These unusual electoral sizes are explained by these areas being island constituencies.

Figure 2 shows in the year to December 2017 the number of Parliamentary electors increased in most constituencies across the UK. The total Parliamentary electorate grew in 480 constituencies (74%) between 2016 and 2017, compared with 583 constituencies (90%) between 2015 and 2016. In the majority (57%) of Parliamentary constituencies the electorate increased between 0% and 1%. In around a quarter of constituencies the number of electors fell, this contrasts with the previous year when very few constituencies saw a decrease in the number of registered electors.

Table 1 shows the 10 areas that experienced the greatest percentage increases in Parliamentary electors between 2016 and 2017.

Most of the areas in the top 10 are home to large numbers of students or are urban areas that are likely to experience high levels of population churn. Nine of the constituencies with the highest growth were in England with one in Northern Ireland (Belfast West). All constituencies in Northern Ireland had increases in the number of Parliamentary electors. The highest percentage increase in Scotland was in Dundee West (4.6%).

Table 2 shows the Parliamentary constituencies that had the largest percentage decreases in size in the year to December 2017. Several of the areas with the largest percentage decreases in the year to December 2017 experienced relatively large increases the previous year. For example, Colchester’s electorate decreased by 3.8% in 2017 but had increased by 10.1% in 2016. A similar pattern occurred in Newcastle upon Tyne Central and Newcastle upon Tyne East.

The total number of UK local government electors in 2017 was 47,932,500, an increase of 1.2% on 2016. Overall, the pattern of change across the UK was like that for Parliamentary electors. The total number of local government electors in each of the UK constituent countries and the percentage changes between 2016 and 2017 was:

• England – 40,246,600, an increase of 1.2%

• Wales – 2,291,300, an increase of 0.9%

• Scotland – 4,121,100, an increase of 0.8%

• Northern Ireland – 1,273,400, an increase of 3.2%

In 82% of local government areas the number of electors increased between December 2016 and December 2017, this was a lower proportion than in the previous year, 92%. The 10 local government areas that experienced the greatest increases in the number of local government electors between 2016 and 2017 are shown in Table 3.

All 10 of the local government areas with the greatest percentage increase were within England. The largest percentage increases in local government electors were in Tower Hamlets (12%) and Nottingham (8.3%). These increases correspond to those seen in the number of Parliamentary electors (Table 1), where Poplar and Limehouse, and Bethnal Green and Bow (both in Tower Hamlets) feature in the areas with the largest increases in electors. Outside of England the largest percentage increase in local government electors was in Derry City and Strabane (4.5%).

All of the 10 areas with the greatest percentage decreases in local government electors were within England and Wales. Three of the areas, Newcastle upon Tyne, South Gloucestershire, and Runnymede are home to large student populations.

Other electoral statistics produced for areas in the UK are as follows.

England

Statistics for Parliamentary electors for electoral wards in England from 2010 to 2017 are available on request from the Boundary Commission for England. These statistics are produced from data collected from Electoral Registration Officers by Office for National Statistics (ONS).

Wales

Statistics for National Assembly for Wales electors by Assembly constituencies are published by the Welsh Government. Those electors who are eligible to vote in local government elections in Wales are eligible to vote in National Assembly for Wales elections. These statistics are produced from data collected from Electoral Registration Officers by ONS.

The data are available from StatsWales (please note their explanation giving details of the impact of boundary changes in some areas).

Scotland

Electoral statistics for Scotland are produced and published by National Records of Scotland (NRS) and cover Scottish Parliament constituencies, Scottish regions and electoral wards.

The data are available from the electoral statistics section of the NRS website.

Northern Ireland

Electoral statistics for Northern Ireland are produced and published by the Electoral Office for Northern Ireland (EONI) and cover Parliamentary and local government electorates at electoral ward level.

The data are available from the electoral statistics section of the EONI website.

Comparing population estimates and electoral statistics

The electoral statistics in this release give information on the number of people who are registered to vote in the UK – there is no similar collection of data on the number of people who are eligible to vote but who do not register.

We provide mid-year estimates of the resident population and these have sometimes been used as an estimate of the total number of people who are entitled to vote. However, care must be taken in using these data for that purpose as the population estimates include some people who are not eligible to vote and exclude some people who are eligible to vote (for example, overseas electors).

We have also published some research looking at the scope and quality of the Electoral Register as a likely source of data for measuring population, which is available in the Administrative Data Sources Report on the Electoral Register (PDF, 554KB).

The Electoral Commission continues to conduct research on voter registration, as well as providing information and guidance to both electoral registration officers and the general public. In July 2016, the Electoral Commission published a report into the accuracy and completeness of the December 2015 electoral registers.

The UK electoral statistics Quality and Methodology Information report contains important information on:

• the strengths and limitations of the data and how it compares with related data

• users and uses of the data

• how the output was created

• the quality of the output including the accuracy of the data

Further information to support the electoral statistics, covering methodology, quality and data sources is available from us:

• the ONS revisions and corrections policy explains how we implement and categorise revisions to statistics

• the transfer of the production of electoral statistics to the Electoral Commission is being considered by the Electoral Commission and ourselves – your views on this potential transfer are welcome; please contact pop.info@ons.gov.uk

• news on our population statistics can be obtained by subscribing to the quarterly newsletter (email your request to population.statistics@ons.gov.uk) or following the Twitter account @richpereira_ONS