In graphs: What you need to know ahead of the triple by-election results

Voters are at the polls today for byelections in Greater London, North Yorkshire and Somerset - three contests in very different parts of the country that will serve as a barometer of public opinion as MPs finish up for the summer break.

Uxbridge and Ruislip, Selby and Ainsty and Somerton and Frome are up for grabs after Boris Johnson, Nigel Adams and David Warburton - all Conservatives - announced their respective resignations, creating an unwelcome triple headache for Rishi Sunak.

Losses for the Conservatives in all of them would be the first time in 55 years that a government has been defeated in three byelections on the same day.

Labour has high hopes of gaining Boris Johnson’s old seat of Uxbridge and South Ruislip on the outer edge of west London.

The Conservative Party has won the seat at every election since it was created in 2010 and the former prime minister won more than half of the vote share in 2019, 2017 and 2015.

At the 2019 general election, Mr Johnson won 25,351 (52.6 per cent) votes, with Labour’s candidate Ali Milani coming in second with 18,141 (37.6 per cent) votes. Liberal Democrat candidate Joanne Humphreys came third on 3,026 (6.3 per cent).

The byelection was triggered after Mr Adams, an ally of Mr Johnson, resigned after being denied a peerage.

But the MP, who previously said he would stand down at the next general election, insisted that his decision to quit had nothing to do with his elevation to the House of Lords being blocked.

Mr Adam, at the 2019 general election, secured 33,995 (60.3 per cent) of the votes, with Labour candidate Malik Rofidi coming second on 13,858 (24.6 per cent) and Lib Dem candidate Katharine Macy third on 4,842 (3.4 per cent)

The Somerton and Frome byelection was sparked by the resignation of David Warbuton, who quit after being accused of sexual harassment, which he denies, and admitting to taking cocaine.

The Somerset seat has been a Conservative stronghold - returning a Tory MP every year since 2010.

The Tories held it from 1983 to 1997 and the Lib Dems from 1997 until 2015, when David Warburton won it back for the Conservatives.

Mr Warburton had a majority of 19,213 at the 2019 election and took nearly 56 per cent of the vote, with the Lib Dems second on just over 26 per cent and Labour third on 13 per cent.

The Lib Dems need a swing in the share of the vote of 14.9 percentage points to come first at the by-election: the equivalent of a net change of 15 in every 100 people switching sides since 2019.