The Conservative government has lost its majority in the House of Commons after MP Phillip Lee defected to the Liberal Democrats.
The MP for Bracknell dramatically joined his new colleagues on the opposition benches, as the Prime Minister addressed Parliament.
The Conservatives along with their confidence-and-supply partner, the DUP, currently hold 320 seats, with the opposition parties with 322.
It is the first time that a sitting government has lost its majority since 1997, when the Conservatives lost their majority under John Major following a series of by-election losses and defections.
His defection comes as Parliament prepares for a showdown between Boris Johnson and the so-called ‘Remain Alliance’ to try and force the Prime Minister to seek an extension to Article 50, should he fail to agree a new deal with the European Union.
It is expected that up to 15 Conservative MPs could rebel and vote with the opposition on the bill.
A number of Tories have announced their intentions to stand down at the next election, following Johnson’s threat to deselect any Conservative MPs who vote against the government today.
The vote is due to take place later this evening.
Meanwhile, former Labour MP Jared O’Mara, who sits as the independent MP for Sheffield Hallam, has postponed his plans to resign. He had announced in July that he would quit after Parliament returned from its summer recess.