New UK prime minister to be announced on September 5

London, July 12: The new UK Prime Minister to replace the outgoing Boris Johnson will be announced on September 5.

The 1922 Committee of Conservative backbench MPs on Monday set out the timetable and rules of play for the elections, which will officially open and also close for nominations on Tuesday. So far, 11 candidates led by frontrunners such as British Indian former minister Rishi Sunak and Foreign Secretary Liz Truss have declared their intention to contest.

"We are very keen that we get this concluded as smoothly, cleanly and rapidly as possible," said Sir Graham Brady, chair of the 1922 Committee "Certainly, we should have a conclusion and a new leader of the party elected and announced on September 5... The crucial thing is we've arrived at the point we're at and we now have a very clear plan to take things forward and resolve the leadership question," he said on Monday.

New regulations voted in by the committee during a crucial meeting earlier on Monday mean Tory members of Parliament who put themselves forward to become the leader of the Conservative Party must have the backing of at least 20 other Tory MPs to get on to the ballot. These candidates will then need at least 30 votes to proceed to the next round, or just under 10 per cent of Tory MPs.

The first ballot will be held on Wednesday and the second ballot on Thursday, when the field is expected to be narrowed down further. There is provision for further ballots next week if the race to get to the final two candidates does not conclude by the end of this week.

Many of the Conservative Party's 358 MPs are yet to declare who they will be supporting, with the shortlist likely to become clearer only as the week progresses.

After the field is whittled down to the final two candidates, they will tour the UK for hustings to campaign the nearly 200,000 Tory party members who will then vote for the winner based on a one member, one vote system.

The candidate who receives the most votes will win the race and be declared the new Tory leader and UK Prime Minister.

Johnson on Thursday announced his resignation as the Conservative Party leader following an unprecedented mutiny from within his Cabinet and after being abandoned by his close allies in the wake of a series of scandals that rocked his government, triggering a leadership election for a new Tory leader who will go on to become his successor.

Johnson, 58, said he will remain in charge at 10 Downing Street until the process of electing a new leader is completed - expected by the time of the Conservative Party conference scheduled for October. He blamed the "herd instinct" of his party as he delivered his resignation speech on the doorstep of 10 Downing Street and expressed his sadness at giving up the "best job in the world."

"I want you to know how sad I am to be giving up the best job in the world," Johnson said in his speech, marking an end to his three tumultuous years in power.

Johnson's term as British Prime Minister will be remembered for setting the India-UK relations on the course of a "Comprehensive Strategic Partnership".

Widely seen as an enthusiastic cheerleader for closer ties with India, Johnson had a palpably close bond with Prime Minister Narendra Modi - someone he would often refer to as his special friend or "khaas dost".