Opinion polling for the 2017 United Kingdom general election was carried out by various organisations to gauge voting intention. Most of the polling companies listed are members of the British Polling Council (BPC) and abide by its disclosure rules. The opinion polls listed range from the previous election on 7 May 2015 to the election on 8 June 2017.
Under the Fixed-term Parliaments Act 2011, the next general election after 2015 was not scheduled to be held until 7 May 2020. However, on 18 April 2017, Prime Minister Theresa May announced she would seek a snap election on 8 June 2017, and this was officially triggered by a successful House of Commons motion the following day.
Most opinion polls do not cover Northern Ireland, which has different major political parties from the rest of the United Kingdom. The Scottish National Party (SNP) only stands candidates in Scotland. Due to rounding, total figures may not add up to 100%. The lead is calculated by subtracting the polling percentage of the first party (shaded in the party's colour, and in bold) by that of the second party.
During the election campaign, YouGov created a Multilevel Regression and Post-stratification (MRP) model based on poll data. As set out by YouGov, the model "works by modelling every constituency and key voter types in Britain based on analysis of key demographics as well as past voting behaviour", with new interviews to registered voters conducted every day.
The general election was contested under the first-past the post electoral system in 650 constituencies. 326 seats were needed for a parliamentary majority.
Most polls were reported in terms of the overall popular vote share, and the pollsters did not typically project how these shares would equate to numbers of seats in the House of Commons.
Various models existed which continually projected election outcomes for the seats in the UK based on the aggregate of polling data. Final predictions of some notable models are tabulated below. 'GB' projections forecast seats in Great Britain only, whilst 'UK' projections also include Northern Irish seats.
An exit poll, conducted by GfK and Ipsos MORI on behalf of the BBC, ITV and Sky News, was published at the end of voting at 22:00, predicting the number of seats for each party.
The exit poll results were regarded as a surprise, as it showed a much closer result than most opinion polls had anticipated.
Some opinion pollsters have asked voters which party leader they would prefer as Prime Minister â Theresa May (Conservative Party) or Jeremy Corbyn (Labour Party). The questions differ slightly from pollster to pollster:
Some polls ask voters to choose between multiple party leaders. The questions vary by pollster: