Rishi Sunak said on Sunday that if he loses the Conservative Party leadership race, his job would be to support the next government, giving the first hint at what's in store beyond Monday's election result to replace Boris Johnson as British Prime Minister.

In his final interview with the BBC before the results are declared, the British Indian former Chancellor said he plans to stay on as a member of Parliament and continue to work for his constituents in Richmond, Yorkshire, if he is defeated by Foreign Secretary Liz Truss in the race.

"I look forward to supporting the Conservative government in whatever capacity," said Sunak, when asked about his future plans if the result does not go his way.

"I'm going to stay as a member of Parliament It's been a great privilege to represent my constituents in Richmond in North Yorkshire as their member of Parliament and I'll love to keep doing that as long as they'll have me," he said.

On whether he would consider a second go at the top job at 10 Downing Street in a few years' time if he loses this time, he said: Gosh, we've just finished this campaign and I need to recover from this one.

This is being seen as the first sign that even the 42-year-old former finance minister believes he may not have got enough votes to clinch the Tory leadership election. With him not ruling out another run, it will also fan speculation that he might want to have a second go at being elected the UK's first Indian-origin Prime Minister if he is beaten by Truss this time.

From being the clear frontrunner in the early knockout stages of the contest with the Tory MPs, Sunak has been trailing Truss in most surveys of party members voting to elect a new leader to succeed Johnson.

Both candidates have gone head-to-head in a dozen hustings events up and down the UK in an attempt to win over votes, with the issue of the cost-of-living crisis as a result of soaring household energy bills and inflation dominating the agenda.

The online and postal ballots cast by an estimated 160,000 Tory members are being tallied by the Conservative Campaign Headquarters (CCHQ), with the winner announced on Monday at 1230 pm local time by Sir Graham Brady chair of the 1922 Committee of backbench Tory MPs and returning officer of the leadership election.

The two finalists in the race will find out who between them has clinched the top job at 10 Downing Street around 10 minutes before the public announcement.

The newly elected Tory leader will make a brief acceptance speech soon after at the Queen Elizabeth II Conference Centre in central London near Downing Street. The rest of Monday will involve the winning candidate putting the final touches to his or her Cabinet posts.

On Tuesday, the day will begin with a farewell speech by outgoing Prime Minister Boris Johnson on the steps of his Downing Street office one last time before he is flown out to Aberdeenshire in Scotland for his audience with the Queen to formally resign as the head of government.

Hours later, his successor will arrive separately in Scotland to be formally appointed Prime Minister by Queen Elizabeth II at her Balmoral Castle residence marking the first time in history that the appointment is made outside of England and Buckingham Palace as the 96-year-old monarch reduces her travels with age.

Later in the afternoon of Tuesday, the newly appointed Prime Minister will arrive back at Downing Street to make his or her inaugural speech before getting on with the task of announcing key Cabinet posts.