Prime Minister Keir Starmer said on Monday he would resign, with a new leader ​to be in place by the time parliament ‌returns in September, paving the way for Britain to have its seventh leader in 10 years.

Here’s what happens next:

HOW DOES A LEADERSHIP CONTEST WORK?

Any ​candidate wishing to replace Starmer would need to secure the ​support of 20% of Labour members of parliament. ⁠With Labour currently holding 403 seats, that equates to ​81 lawmakers, including the challenger.

Candidates also must hit thresholds ​for support from grassroots Labour Party organisations, and from affiliated organisations such as trade unions.

WHO GETS TO DECIDE THE WINNER?

If more than ​one candidate qualifies, the winner is decided by a ​ballot of all Labour Party members and affiliates. The winner then becomes ‌prime ⁠minister.

HOW LONG WOULD IT TAKE?

Though the timeline is officially decided by the party’s governing body, Starmer said nominations would open on July 9 and close before parliament goes ​into recess, which ​is scheduled ⁠for July 16.

He said if there were to be a contest, it should be ​completed by the time parliament returns, which ​is scheduled ⁠for September 1.

WHAT HAPPENS IF THERE’S ONLY ONE CANDIDATE?

If only one candidate meets the threshold for support, there is ⁠no ​vote: the candidate is elected unopposed ​as Labour leader and becomes prime minister.