If Boris Johnson resigned, there would not automatically be a general election to replace him.
Instead, the Conservative Party should choose its next leader, who would become prime minister. Over the decades, James Callaghan, John Major, Gordon Brown, Theresa May and Mr Johnson himself all initially took over after internal party changes without a general election.
Under Conservative Party rules, the vote for a new party leader would take place in two stages: First, Conservative MPs would put their names forward and undergo a series of votes until only two candidates were left. Party members would then be called upon to vote for one of the two.
The timing for each game is set by a group known as the 1922 Committee, which represents conservative backbenchers.
Under Tory rules, Mr Johnson would normally be expected to remain in the position until a new leader is elected, as Ms May did in 2019 and David Cameron in 2016. But he could resign and recommend the Queen a new one. Prime Minister to fill that position until the Conservatives appoint a new leader.
Ms May, who survived a vote of no confidence in December 2018, announced her resignation within six months of her win. Then there was an election. Johnson and his opponent, Jeremy Hunt, who were chosen as the party’s finalists, spent six frenetic weeks campaigning for a vote among 160,000 members of the party.
If Mr Johnson insists on remaining in office, the rules say he cannot face mistrust for another year as he faced it last month. But those rules can be changed by the higher hierarchy of the Conservative Party in parliament.