After several weeks of jostling, the candidates to replace Theresa May have begun officially launching their campaigns.
Eleven MPs are expected to put their name forward, and by July 22 they’ll be whittled down to one.
So how does the process work?
The race offically begins
Ms May resigned on Friday, and is no longer the head of the Conservative Party.
She’ll remain as interim Prime Minister and live at Downing Street until her successor is appointed.
At 5pm on June 10 there will be an official call for candidates from the 1922 Committee of Tory backbenchers, which is in charge of the leadership vote.
Anyone with leadership ambitions will need the support of eight MPs to put their name forward.
Elected by their peers
The race starts straight away.
On June 11 and 12 candidates will take part in hustings events. These are only for fellow Conservative MPs and no media will be allowed access.
On June 13 the first round of voting takes place in Committee Room 14 in Parliament.
Candidates need the support of at least 17 MPs to move on to the next round.
They may also choose to drop out if they feel they don’t have a chance of victory.
From June 17 the remaining candidates take part in a second hustings event and a second round of voting.
This time candidates need the support of 33 MPs to avoid being knocked out.
If every candidate reaches this figure, the person with the lowest number of votes is removed.
These votes will continue through June 19 and 20 until only two candidates remain.
The MPs have then played their role, and the vote will move to the party members.
Taking it to the members
On June 22 the final two candidates will begin travelling across the country holding hustings events in front of party members.
There are around 124,000 Conservative Party members who all get a vote for the new leader.
Party members are expected to have sent in their postal ballot by 5pm on July 22, and the 1922 Committee may announce the new Prime Minister as quickly as the next day.
Ms May could then immediately resign as Prime Minister and hand the reins to her successor, or allow for a brief transition period.