How will a new prime minister be selected - and when will it happen?

Sir Keir Starmer has announced he will resign and a contest to replace him as Labour leader and prime minister will take place.

Andy Burnham, who became an MP on 18 June after winning the Makerfield by-election, is looking likely to be crowned leader - but two senior Labour figures are said to be weighing up a leadership bid to avoid a coronation for the former Greater Manchester mayor.

Politics latest: Starmer resigns as prime minister

Key dates and how a Labour leadership contest works

Labour's ruling body has yet to formally confirm the timetable.

But Sir Keir has said he would like nominations to open on 9 July - a day after the NATO summit, which he looks likely to attend.

Any Labour MP who wants to be on the final ballot will have to get the backing of at least 20% of Labour MPs, which is currently 81 (including themselves).

Candidates must also be nominated by at least 5% of constituency parties, or at least three "affiliates" - two of which must be trade unions - which represent a minimum of 5% of the affiliated membership.

Labour Party affiliates consist of 11 major trade unions, Labour's sister Co-operative Party, and more than 20 socialist societies.

When will nominations close?

Labour's ruling body, the National Executive Committee (NEC), has said it will agree a timetable for the election of the next leader "shortly".

Sky News understands it could be 16 July, when parliament begins its summer recess.

Who can vote?

After nominations close, all Labour Party members who have continuously been members for at least six months before the timetable is announced are eligible to vote.

Each eligible voter has just one vote, so they cannot vote as an individual and as a trade union member.

Members vote by ranking candidates in order of preference (the alternative vote system).

How many votes are needed to win?

The winner must receive more than half of the votes cast.

If no candidate receives that total as a first preference, then votes are redistributed according to preferences until one candidate secures at least half the votes.

When will a new leader be in place?

A winner is usually announced a couple of days after nominations close.

Starmer said following a contest, a new leader will be in place by 1 September, when parliament returns from recess.

What happens if only one MP gets enough nominations?

Then that's the end of the contest. That MP will become leader of the Labour Party, and therefore prime minister.

Sky News understands the new leader would then be in place shortly after the vote, by 17 or 18 July - so they, not Sir Keir, would be in post for the World Cup final on 19 July as PM.

They would have been flung straight into an EU summit in Brussels on 22 July to discuss the "reset" in relations between London and the EU. However, the EU has now said it will postpone the summit because of the PM resigning.

Mr Burnham has previously supported rejoining the EU in the "long-term", but recently denied he would campaign for it.

Read more: The charts that tell us why Starmer resigned

Who will stand?

Mr Burnham, who won the Makerfield by-election on Friday, has said he will stand, with allies saying he is hoping for at least 200 nominations.

Wes Streeting, who recently resigned as health secretary over Sir Keir's leadership, previously said he was going to stand, but he has now said he will not and will back Mr Burnham instead.

Two senior MPs are said to be weighing up a leadership bid against Burnham in order to force a contest. Darren Jones, Sir Keir's chief secretary, is said to be mulling a bid. Although sources close to Mr Jones said he was not currently minded to run, and he wanted assurances from Mr Burnham on economic policy.

Sources close to Al Carns, who resigned as armed forces minister a fortnight ago in a row over defence spending, told Sky News he was not ruling out a leadership bid.

Sir Keir will not stand, even though he would automatically be on the ballot if he wanted to.

Any Labour MP could put themselves forward, but they must get 80 other MPs to support them to be on the ballot paper.

Due to numbers, a maximum of five MPs can be on the ballot paper.

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