The Electoral Commission

The independent body which oversees elections and regulates political finance in the UK

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2. The size of the electoral register

An estimated 46.8 million people were registered to vote at the June 2017 UK Parliamentary general election. This was the largest electorate for a UK-wide poll, with approximately 500,000 more electors than at the 2015 general election and 300,000 more than at the 2016 EU referendum.

The total number of people registered to vote across the UK also increased by approximately 1.4 million between the end of the annual canvass on 1 December 2016 and the June 2017 election. Chart 1 below shows the changing size of the UK’s electoral registers at UK-wide electoral events (including UK Parliamentary general elections and European Parliamentary elections) and at the conclusion of the annual canvass each year since 2009.

There was some variation in the volume of change in the constituency electorates between May 2015 and June 2017. Four constituencies saw a fall in the total number of registered electors of just over 10% since the last general election (Ilford South, Glasgow North, Glasgow North East and Merthyr Tydfil and Rhymney) while two saw increases of 10% or more (Bridgwater and West Somerset, and Leeds North West). Bridgwater and West Somerset saw the largest absolute increase of 8,803 electors while Ilford South recorded the largest absolute decrease of 9,500 electors.

The size of electoral registers fluctuates over time and there were also changes in the registered electorate in the shorter period between December 2016 and June 2017. This is not surprising as the electorate increases ahead of a major poll to reflect population movement, and commonly decreases after the subsequent canvass. We would therefore expect greater similarity between two sets of general election registers (in a short period) than between a set of December registers and those used at a general election.

Chart 1: The changing size of the UK’s electoral registers 2009-17

Chart showing the changing size of the UK electoral registers

Unsurprisingly therefore a larger number of constituencies saw increases in their electorate between December and June and the size of any decreases was not as great. Increases in electorate of over 15% were recorded in Bethnal Green and Bow, Poplar and Limehouse and Leeds North West constituencies. There were also notable increases of more than 10% in constituencies with high concentrations of students (Canterbury, Cambridge, Brighton Pavilion, Bristol West and Leeds Central).

Our briefing paper issued after the March 2017 Northern Ireland Assembly elections highlighted concerns that nearly 3,500 people attended polling stations in order to vote but were found to be not registered. We are aware that 1,862 people in Northern Ireland were turned away at the June UK general election for the same reason. Although this was a significant reduction in the number of people unable to vote because they were not correctly registered, it was nonetheless disappointing that a significant number of people could not vote.

Elections and referendums