In the UK, having the support of the House of Commons has long been regarded as essential to a government's ability to rule.
Historically, governments that have lost a vote of confidence have either resigned to make way for another administration or the prime minister has asked the working monarch to dissolve Parliament, which results in a general election.
Former prime ministers Boris Johnson and Liz Truss have both faced no-confidence votes.
Reasons for declaring the vote in Johnson’s premiership included the fallout over Sue Gray’s partygate report.
However, his government at the time survived the vote.
But what does a vote of no confidence mean and how does it work?
What is a vote of no confidence?
A vote of no confidence is when MPs across all parties vote on whether they want to keep their leader.
It is a way to see if the prime minister still has the support of their party in the House of Commons.
How does a vote of no confidence work?
A vote of no confidence is triggered when 15 per cent of sitting Tory MPs write to the executive committee saying they no longer have faith in the prime minister. Currently, 15 per cent equates to 52 people.
Sir Graham Brady, chairman of the 1922 committee of backbench Conservative MPs, said he had received at least 54 letters from MPs while Johnson was still in control but hasn’t specified the amount he received for Truss.
All Tory MPs will vote on whether they still have confidence in the leader.
The prime minister will need 180 votes to win the vote of confidence.
What is the 1922 committee?
The 1922 Committee is a committee of backbench Conservative MPs. They meet weekly when the Commons is sitting.
It was established in April 1923 after an initiative by Conservative MPs elected at the 1922 General Election. Its aim is to facilitate co-operation within the party.
Sir Graham Brady has been chairman of the 1922 committee since 2010. He briefly resigned in 2019, before being re-elected in 2020.
What happens if the vote passes?
If the prime minister wins the vote, he will stay as leader. If he loses, he will have lost the confidence of his party and the incumbent government must resign, or call a general election.
When was the last vote of no confidence?
The last time a vote of confidence took place before Boris Johnson’s in June was in 2018.
Then-prime minister Theresa May won the vote but was forced to resign months later.
