Under the UK political system, between elections, only Conservative members of Parliament have the power to remove a sitting Conservative Prime Minister.
So, what happens to UK government when a Prime Minister resigns, and how is a new leader elected?
No. It starts the Conservative Party process for choosing a new leader of the party.
UK Prime Ministers are not directly elected by the people; Johnson is Prime Minister because he is the head of the largest party in the House of Commons.
The Conservatives will still be the largest party even if Johnson resigns, so the new head of the party will become Prime Minister.
How is the new Conservative Party leader chosen?
Leadership candidates need the support of at least eight lawmakers.
If there are more than two candidates, Conservative Party lawmakers hold round after round of votes to whittle the number of leadership candidates down to two.
Then Conservative Party members nationwide vote — by mail — between the two finalists.
The winner becomes leader of the party — and Prime Minister.
Source : Nbcnewyork