Electoral statistics, UK: 2016

• The total number of UK parliamentary electors increased by just over 1 million (2.3%) between December 2015 and December 2016, this partly reflects high levels of public engagement with the EU referendum.

• The total number of UK local government electors also increased by just over 1.1 million (2.5%) between December 2015 and December 2016.

• Of the 650 parliamentary constituencies in the UK, 583 (90%) had an increase in parliamentary electors between December 2015 and December 2016.

• The number of UK parliamentary and local government electors increased in England, Wales and Scotland but decreased in Northern Ireland.

“In the year to December 2016 the number of people registered to vote in parliamentary and local government elections across the UK increased by around 1 million. In the previous 2 years the number of people registered to vote had decreased partly as a consequence of the introduction of Individual Electoral Registration (IER). A key driver of the increase in the size of the electorate in the year to December 2016 was public engagement with the EU referendum in June 2016.”

Neil Park, Population Statistics Division, Office for National Statistics

Electoral statistics are available for the 2 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 largely depends 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 3 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

In particular the introduction of Individual Electoral Registration (IER) in 2014 has introduced new administrative practices. Although IER does not change who is eligible to vote, it may have changed the proportion of those eligible that are registered to vote. More information on IER is available in the section on related information.

For England and Wales, electoral statistics are taken from data supplied to the 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 2016 was 45,766,000, an increase of 2.3%, around 1 million, from December 2015.

The total number of parliamentary electors in each of the UK constituent countries and the percentage changes between 2015 and 2016 are:

• England – 38,386,900, an increase of 2.6%

• Wales – 2,243,900, an increase of 2.8%

• Scotland – 3,930,000, an increase of 0.8%

• Northern Ireland – 1,205,700, a decrease of 3%

Figure 1 shows the different patterns of change in parliamentary electors between the UK constituent countries over the last 6 years. Between December 2015 and December 2016 the number of electors increased in England, Wales and Scotland but decreased by 3% in Northern Ireland. This is the opposite of the pattern observed in the 2 years between 2013 and 2015 where the electorate in Northern Ireland increased but decreased across the other 3 countries of the UK.

The reduction in the number of parliamentary electors in Northern Ireland between 2015 and 2016 can be substantially explained by the removal of 60,000 names from the register who did not return an electoral registration form during the last canvass of electors in 2013. These names were retained on the register given that scheduled elections took place between 2014 and 2016. However, the law required that anyone who had not completed a registration form during this time must be removed by 1 December 2016. Further information can be found on the Electoral Office for Northern Ireland website.

The increase in the electorate across the rest of the UK between 2015 and 2016 is partly the impact of the EU referendum on levels of voter registration and partly reflects the completion of individual electoral registration the previous year.

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 2016, the median total parliamentary electorate across constituencies was about 55,700 in Wales, 65,900 in Northern Ireland, 66,800 in Scotland and 71,700 in England.

In 2016, the parliamentary constituency with the smallest sized electorate at 21,200 was Na h-Eileanan an Iar and the largest electorate at 108,600 was the Isle of Wight. These unusual electoral sizes are explained by these areas being island constituencies.

Figure 2 shows in the year to December 2016 the number of parliamentary electors increased in most constituencies across the UK. The total parliamentary electorate grew in 583 constituencies (90%) between 2015 and 2016, compared with 198 constituencies (30%) between 2014 and 2015. In just under a third of parliamentary constituencies the electorate grew between 0 and 2%, while in around 50% of areas the electorate grew by between 2% and 5%.

Table 1 shows the 10 areas that experienced the greatest percentage increases in parliamentary electors between 2015 and 2016.

Several of the areas in the top 10 (Cardiff Central, Lancaster and Fleetwood, Leeds Central, Lewisham, Deptford and Sheffield Central) are home to large numbers of students or are urban areas that are likely to experience high levels of population churn.

Three of the constituencies in the top 10, Crewe and Nantwich, Congleton and Macclesfield fall entirely, or at least mostly, within the Cheshire East unitary authority.

Table 2 shows that 6 of the 10 parliamentary constituencies with the greatest decreases in size were in Northern Ireland, reflecting the removals highlighted in section 4. Two constituencies in Manchester, Withington and Gorton, were also in the top 10. The decrease in parliamentary electors can be at least partly explained by activities related to the December 2015 canvass of electors in Manchester that occurred in early 2016.

The total number of UK local government electors in 2016 was 47,350,700, an increase of 2.5% on 2015.

Overall, the pattern of change across the UK is very similar to that for parliamentary electors. The total number of local government electors in each of the UK constituent countries and the percentage changes between 2015 and 2016 are:

• England – 39,756,900, an increase of 2.7%

• Wales – 2,270,400, an increase of 2.8%

• Scotland – 4,089,500, an increase of 1.5%

• Northern Ireland – 1,233,900, a decrease of 2.9%

In 92% of local government areas the number of electors increased between December 2015 and December 2016. The 10 local government areas that experienced the greatest increases in the number of local government electors between 2015 and 2016 are shown in Table 3. The top 4 positions are held by local government areas (Colchester, Croydon, Cheshire East and Lancaster) that cover the constituencies that had the greatest increases in parliamentary electors.

The administrative processes that led to a reduction in the number of parliamentary electors across Northern Ireland and Manchester also affected the number of local government electors. Seven of the 10 areas that experienced the greatest percentage decrease in local government electors were in Northern Ireland.

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 2016 are available on request from the Boundary Commission for England. These statistics are produced from data collected from Electoral Registration Officers by 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 (554 Kb Pdf).

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 document 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 @paulvickers_ONS