Electoral statistics, UK: 2018

• The total number of UK Parliamentary electors decreased by 372,000 (0.8%) between December 2017 and December 2018, compared with an increase in the previous year.

• The number of electors was at a high point in the year to December 2017, following three successive years with national polls, in contrast with the decrease in electors seen in the latest year, to December 2018.

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

“The number of people registered to vote in UK parliamentary elections has fallen for the first time since 2015. This follows major national votes three years running – two General Elections and the EU Referendum, which pushed electoral registration to a five year high in 2017.

The fall in electoral registrations in 2018 is partly driven by population change as a relatively high number of deaths as well as a small cohort of 18-year-olds mean more people left the electoral register than joined. Another driver of the fall in the number of parliamentary electors was a 45% reduction in the number of registered voters living overseas following large increases in the preceding years.”

Neil Park, Centre for Ageing and Demography, 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 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 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, 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.

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.

What’s new in this release

In previous years the electoral statistics release has been followed by later publications of additional data. For the 2019 release these tables have been published as part of the regular annual release. The tables provide data on overseas electors, anonymous electors, electors opted out of the open register, and Parliamentary electors on local government boundaries. These additional tables only cover England and Wales.

The 2019 release of electoral statistics (referring to 1 December 2018) includes several changes to local authority names, codes and boundaries. These are detailed in the Quality and Methodology Information report.

The total number of UK Parliamentary electors in December 2018 was 45,775,800, a decrease of 372,000 (negative 0.8%) from the previous year.

The total number of Parliamentary electors in each of the UK constituent countries and the percentage changes between 2017 and 2018 was:

• England – 38,371,400, a decrease of 0.8%

• Wales – 2,230,100, a decrease of 1.4%

• Scotland – 3,925,800, a decrease of 0.6%

• Northern Ireland – 1,248,400, an increase of 0.5%

Figure 1 shows the change in the number of Parliamentary electors for UK constituent countries over the last two years. While all four UK countries saw an increase in their parliamentary electorates in the year to December 2017, only Northern Ireland had an increase in the year to December 2018. In Northern Ireland the number of electors increased by 0.5% in 2018 following a 3.0% increase in the year before.

The number of electors in Wales decreased by 1.4% in the year to December 2018. This is the largest percentage decrease seen since the year to December 2015 when the number of electors decreased by 2%. Scotland and England had a decrease of 0.6% and 0.8% respectively in the year to December 2018, compared with increases in the previous year.

In December 2017 the number of parliamentary electors was at its highest since December 2012 following three successive years with national polls. This is at least partly due to campaigns encouraging eligible voters to register being held across the country during the EU referendum in June 2016, and also for the May 2015 and June 2017 General Elections.

In Section 3, “Things you need to know about this release”, three potential drivers of change in the number of registered electors were mentioned. There is some evidence for the first of these, population change, driving the change in electors in this year’s statistics. Over the last few years the number of deaths across the UK has increased (partly linked to the increasingly old age structure of the population) and the number of those aged 18 years has decreased (this is mostly due to small birth cohorts around the millennium). At a simplistic level this means that the flow of people off the register (largely through deaths) has increased and the flow of people on to the register at age 18 years (16 years for local government electors in Scotland) has fallen. It is important to note that not all those becoming eligible to vote immediately register to vote.

In parts of the UK with younger age structures (such as Northern Ireland) there have been increases in the size of the electorate while in areas with older age structures (Scotland, Wales and the North East of England in particular) there have been decreases.

The tables published alongside this report provide the number of electors in the latest and previous year for each Westminster Parliamentary Constituency. Figure 2 shows the 10 areas that experienced the greatest percentage increases in Parliamentary electors between December 2017 and December 2018.

With the exception of Paisley and Renfrewshire North and South in Scotland, the 10 biggest percentage increases were all in England. Three of these areas, Thornbury and Yate, Filton and Bradley Stoke and Kingswood are all partly or entirely within South Gloucestershire. The other five areas are spread across England.

Figure 3 shows Parliamentary constituencies with the largest percentage decreases in electors in the year to December 2018. Most of the areas with the largest percentage decrease in the year to December 2018 experienced relatively large increases the previous year:

• City of Durham decreased by 11.3% in the year to December 2018 but increased by 7.3% the previous year

• Nottingham South decreased by 9.1% in the year to December 2018 but increased by 11.6% in the previous year

• Nottingham East declined by 7.4% in the year to December 2018 but increased by 7.5% in the previous year

The total number of UK local government electors in the year to 2018 was 47,785,500, a decrease of 0.3% on 2017.

Overall, the pattern of change across the UK was 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 2017 and 2018 was:

• England – 40,133,400, a decrease of 0.3%

• Wales – 2,264,700, a decrease of 1.2%

• Scotland – 4,105,800, a decrease of 0.4%

• Northern Ireland – 1,281,600, an increase of 0.6%

All counties saw a decrease in their local government electorates except Northern Ireland, which increased by 0.6%. In the year to December 2017, all four UK countries saw increases in their local government electorate. The 10 local government areas that experienced the greatest increases in the number of local government electors between 2017 and 2018 are shown in Figure 4.

All 10 local government areas with the greatest percentage increase were within England, apart from Renfrewshire in Scotland. The largest percentage increase in local government electors was in Barking and Dagenham (4.5%). This is likely to be partly demographically driven by relatively low numbers of deaths (people leaving the electoral register) and a relatively large cohort of 18-year-olds able to join the register in this area.

Figure 5 shows the 10 areas that had the greatest percentage decrease in local government electors in the year to December 2018. While the Isles of Scilly had the largest decrease (7.1%) it should be remembered that the total number of local government electors there is very small (around 1,600) and that annual percentage change can often be volatile as a result. Nottingham had the second largest percentage decrease of 6.3% and Dundee City decreased by 3.9%.

Many of the areas with the biggest percentage decreases in electors in the year to December 2018 have large student populations. The populations in student areas tend to experience consistently high levels of migration (both within the UK and internationally) as students migrate to and from places of study. Further the populations in these areas tend to have disproportionately high levels of people aged 18 and 19 years who have only been eligible to vote for a short period. In recent years, areas with large numbers of students or other populations with high levels of population churn have tended to see more annual changes (both increase and decreases) in their electoral rolls than elsewhere.

The interactive maps in Figure 6 show the percentage change in local government electors for the last three years for the UK and the change in the number of parliamentary electors (on local government boundaries) for the last year in England and Wales.

Figure 6: Following two years of almost universal increases in the numbers of registered electors, 2018 saw a decrease in electors in most areas

In the year to 2016, 92% of local government areas saw an increase in the number of local government electors; for 2017 the proportion was nearly 82% while for the year to 2018 just 43% of areas saw an increase. Part of the explanation for this pattern is that both 2016 and 2017 had national elections (the EU Referendum in 2016 and a General Election in 2017) while 2018 did not.

The map showing the change in parliamentary electors for the year to 2018 shows larger decreases in the number of registered electors than the local government equivalent. Part of this change is driven by a decrease in the number of electors registered overseas who are not eligible to vote in local government elections

For this release we’ve included counts of the number of electors registered overseas for regions in England and for Wales. This data has previously been published later in the year following the release of the Electoral Statistics.

Figure 7 shows the number of overseas electors decreased between December 2017 to 2018. England had a decrease of 44.7% and Wales 47.4%. The pattern of change in the last two years contrasts with the years immediately preceding them, where there was a sharp increase in the number of overseas electors. In the year to December 2016 there was an increase of 157.4% of overseas electors for England and 147.1% increase for Wales. Figure 7 shows an increase of electorates in the year to December 2016, due to there being overseas voter registration campaign (PDF, 5MB) in the run up to the 2015 General Election and interest in the 2016 referendum on the UK’s membership of the EU.

For this release we’ve included counts of the number of electors opted out of the open register for local government areas in England and Wales. This data has previously been released later in the year. Further information on opting out of the open register is available.

The year to December 2018 saw the highest number of people opting-out of the electoral register. Between 2013 and 2018 the number of electors opted out of the open register increased by 11.1 million (76%) to 25.7 million.

For this release we’ve included counts of the number of anonymous electors in England and Wales. This data has previously been published later in the year. Further information on anonymous electors is available (PDF, 112KB).

While the number of anonymous electors makes up only a small proportion of the total electorate (around 1 in 20,000), the number has doubled from 1,258 in the year to December 2010 to 2,550 in the year to December 2018 in England.

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 the 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 Office for National Statistics (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