Philip Lee has crossed the floor during Prime Minister Boris Johnson’s speech in the House of Commons to join the Liberal Democrats, wiping out the Conservative government’s majority.

Mr Johnson was addressing the Commons on Tuesday afternoon when the MP for Bracknell took his seat in the opposite benches, with the prime minister breaking flow of his speech to remark: “I wish my honourable friend all the best.”

In his resignation letter, Mr Lee had claimed that the Tory Party “had become a narrow faction in which one’s Conservatism is measured by how recklessly one wants to leave the European Union”.

“That is why today I am joining Jo Swinson and the Liberal Democrats,” the former justice minister continued.

The resignation is highly significant as Johnson is now overseeing a minority government, increasing the likelihood of a snap election in coming weeks.

MPs returned to the House of Commons today after the six-week recess, with a Remainer plot afoot to take over the lower chamber and pass a bill to stop the UK leaving the EU on October 31st in a no deal. The plans are backed by Opposition MPs as well as some 20 Tory rebels, who have been warned that they will be kicked out of the Conservative Party if they vote against the government.

While telling the public last night that he did not want an election, a Downing Street source said later that evening that Mr Johnson would ask the House to trigger a snap election on October 14th should his Brexit plans be thwarted — and the prime minister may be forced to make good on that threat after losing his majority.

Earlier today, Prime Minister Johnson is said to have met with members of the rebel Remainer alliance to ask them not to vote against the government, reportedly telling them: “You are handing power over to a junta that includes Jeremy Corbyn.”

During his speech on the G7 summit in the Commons, Mr Johnson asked his colleagues to reject “Jeremy Corbyn’s surrender bill”, saying it would weaken his negotiating hand and jeopardise his chances of agreeing an altered withdrawal treaty with the EU, and that to defeat the government would meaning “running up the white flag” to Brussels.

If Speaker Bercow accepts the motion, there will be a debate from 6:30pm with a vote on taking over the House between 9pm and 10pm. If the motion passes, there could be a vote on the bill to stop no deal as early as tomorrow, likely resulting in the prime minister asking the House on Wednesday to trigger a General Election.