Rules of a Labour leadership contest explained and who can vote in it

 Keir Starmer could become the first sitting Labour PM to face a leadership challenge, with rumours swirling after a disastrous set of election results.

No leadership challenge has been made, but following the resignation of the Health Secretary Wes Streeting, the Prime Minister's leadership is hanging in the balance, with over 80 MPs publicly called on him to resign.

Mr Streeting criticised the “drift” at the top of Government and told the PM it is “clear” he will not lead Labour into the next election.

While stopping short of announcing a bid for the top job, Mr Streeting urged the PM to allow the “best possible field of candidates” to run to replace him in Downing Street, suggesting he could be in favour of including Andy Burnham.

Here's how a leadership contest works, how it's triggered, and who can vote.

How is a leadership contest triggered?

Ousting a Labour leader begins with MPs forcing a leadership election. This requires 20% of the party's MPs to back a replacement candidate, which would mean 81 MPs as the Labour party has 403.

Once the leadership election is triggered, other candidates can join if they also have 81 backers. The PM would not be required to have 81 backers as he would automatically be on the ballot if he chose to run, which Mr Starmer is expected to do. Even if he did need backers, more than 110 MPs signed a letter suggesting they'd support him this week. Mr Starmer would continue as PM during the contest, and be the first Labour PM to ever face a leadership challenge.

Who can stand?

Only Labour MPs are eligible to stand, meaning Andy Burnham, the Greater Manchester Mayor would require a seat if he were to stand for the leadership.

How long does a contest last?

Once a candidate has 81 backers, the National Executive Council (NEC) — Labour Party's ruling body — begins arrangements for a full vote with party members. In 2020, candidates had time to secure their nominations before a ballot took place over a six-week period.

Hollie Ridley, the Labour general secretary, would act as returning officer in the election and would be required to appoint an independent scrutineer to oversee and verify the ballot. They set the timetable, so there is no set time.

Who can vote?

Candidates need to impress not just party members, but also affiliated trade union supporters who then rank candidates in order of preference. The unions include Unite the Union, Unison, and GMB. The party has used a one-person-one-vote system for leadership elections to ensure that the same person cannot vote twice for being trade union member and a Labour Party member.

If I join the Labour party today, can I vote?

No. Members must have six months membership at the start of a formal leadership contest to qualify for a vote.

How is a winner decided?

Voting takes place using a preferential ballot, with members ranking the candidates in order of preference. If a candidate secures over 50% of the first preference votes, they are declared the winner and will become the new Labour leader, or in Mr Starmer's case, keep his job.

If that doesn’t happen, the candidate who places last is eliminated and the voters who put them as their number one choice will have their votes moved to their second choice candidate. The process continues until one candidate secures more than 50% of the votes cast.