Theresa May has vowed to remain loyal to her successor as prime minister, as she prepares to step aside for either Boris Johnson or Jeremy Hunt.

The PM said she would do “everything I can” to ensure there is a Conservative government, and confirmed that she had voted in the final round of the Tory leadership contest.

Frontrunner Mr Johnson is widely predicted to beat Foreign Secretary Mr Hunt to be announced as the next party leader on Tuesday, and Mrs May will stand down the following day.

In an interview with the Daily Express, Mrs May was asked whether she would remain loyal to her successor.

She replied: “Absolutely. It is important that we have a Conservative government, particularly given the nature of the opposition we have at the moment.

“I will be doing everything I can to make sure that we have a Conservative government.”

Tory leadership contest timetable
(PA Graphics)

Her comments came after Chancellor Philip Hammond fired a warning shot to Mr Johnson, saying he would do “everything in my power” to block a no-deal Brexit and left open the possibility of voting to bring down a Conservative government in such an event.

Mrs May said she had not told anyone, including her husband Philip, who had won her vote, and said she does not have any plans “at the moment” to write a memoir recounting her time in Number 10.

“There are those who say that people who are involved with matters of national significance should put something down about how they saw it at the time for future historians, but I’ve not got any plans at the moment,” she told the paper.

“I’m going to take some time off, have a holiday and adjust to the new world.”

Mrs May also said she had been “touched by the huge amount of support I’ve received from the public” including gifts, flowers, letters and emails after announcing her intention to stand down.

Her comments came after US president Donald Trump said Mr Johnson will do a “great job” if he becomes prime minister next week.

Mr Trump said he thought he would have a “great relationship” with the former foreign secretary and repeated his criticism of Mrs May’s handling of Brexit.

The president said: “I like Boris Johnson. Boris, I spoke to him yesterday. I think he’s going to do a great job. I think we’re going to have a great relationship.”

He added: “I think they’ve done a very poor job with Brexit. I think the previous prime minister has done a very bad job with Brexit. What can I say? I mean it’s a disaster and it shouldn’t be that way. I think Boris will straighten it out.”