Results and turnout at the 2015 UK general election

The UK electorate at the 2015 general election was almost 46.4 million –the largest ever. The registers contained three-quarters of a million more names than in 2010 –an increase of 1.7%. 

More than a million people registered to vote in the period between the compilation of the ONS parliamentary electorate statistics based on the registers at 1st December 2014 and the general election in May. 

Nearly 30.7 million valid votes were cast, making the overall turnout across the UK 66.2%. This is one million more votes than in 2010, but only a 1.1 percentage point higher turnout. 

The ‘ballot box’ turnout which includes votes rejected at the count was 30.8 million or 66.4% of the registered electorate. 

Turnout rose in each country, but jumped particularly sharply in Scotland from 63.9% in 2010 to 71.1%. 

The number of ballot papers rejected at the count continues to be but a small fraction of the total cast (0.33%), though was a little greater than in either 2010 or 2005. There is evidence of the rejection rate being somewhat higher where voters are faced with an additional election, especially in cases where it operates under a different electoral system (e.g. in those areas with a coincident mayoral election). 

Almost 7.6 million postal votes were issued -16.4% of the entire electorate. This represented an increase of 1.1 percentage points and more than half a million more voters than in 2010.

85.8% of those with a postal ballot returned it. By way of contrast, only 63.2% of those electors required to vote ‘in person’ did so.

The number of postal votes at the count was one in five of the total. In the North East region of England more than a third of all votes were cast by post.

The proportion of postal votes rejected or otherwise not included in the count was 3.3%. It was less than in 2010 in every country of the UK.

In about half the cases postal votes were rejected because a signature or date of birth (or both) were mismatched; in another quarter because the elector omitted to enclose either the ballot paper or the postal vote statement (or both). 

Almost 150,000 electors (0.3% of the total) appointed proxies. This was a small increase compared with 2010, concentrated especially in Scotland and Northern Ireland. The number of emergency proxy votes increased from fewer than 1,000 in 2010 to nearly 9,000 following a relaxation of the rules regarding eligibility.

About three fifths of one percent of electors with a postal vote were granted a waiver to use their date of birth as their sole identifier. This is in line with levels seen at the 2014 European Parliament contests.