The former Downing Street adviser said he was pulling out of the race "with a heavy heart" as he continued to deny the allegation made by Daisy Goodwin.

Ms Goodwin said she was "glad" he had withdrawn as it "shows that women can speak out against misbehaviour in the workplace and be believed".

Politics latest: Tory mayoral race down to two after Korski withdrawal

In a statement announcing his decision, Mr Korski said: "I categorically deny the allegation against me. Nothing was ever put to me formally 10 years ago. Nor seven years ago when the allegation was alluded to.

"No investigation has ever taken place. I have been clear I would welcome and constructively participate in any investigation.

"However, the pressure on my family because of this false and unproven allegation and the inability to get a hearing for my message of 'The London Dream' makes it impossible for my campaign to carry on."

In a message to his campaign team, Mr Korski said he wanted to address the "troubling state of our political landscape".

He claimed "dirty tactics, smear campaigns and underhanded strategies have plagued this process, threatening the integrity and honesty that should define our party".

Accuser 'feels entirely justified'

Ms Goodwin wrote in The Times earlier this week about her claim that Mr Korski groped her following a meeting 10 years ago in Downing Street.

Following his decision to pull out of the mayoral race, she said: "I am glad he has withdrawn - it shows that women can speak out against misbehaviour in the workplace and be believed."

Ms Goodwin had earlier said that "other women" had since been in contact with her about some "very interesting stories, which clearly I can't talk about for legal reasons".

"I feel entirely justified in having written a piece and naming him," she added.

At the time of the alleged incident, Mr Korski was working as an adviser to then prime minister David Cameron.

Ms Goodwin said she had only come forward to name Mr Korski this year because he was standing for public office.

She did, however, write about the allegation in 2017 - albeit without naming Mr Korski.

Korski 'told Tory party about allegation during vetting'

After he was accused by Ms Goodwin, Mr Korski was asked if the allegation had been disclosed to the Conservative Party in his vetting to be a mayoral candidate.

He told TalkTV: "Yeah, during the process, I was asked about if there were any outstanding issues the party may be aware of.

"And I said to the party, seven years ago, there was a story. I was never named in the story.

"As far as I know, there was no investigation. But I did mention this to the party."

Tory members will vote from 4 to 18 July on their preferred choice for the London mayoral election next year, with the winner announced on 19 July.

The race will see Ms Hall and Mozammel Hossain face down head-to-head, the Conservative Party confirmed, with no new candidates added.

One of Mr Korski's backers told Sky News that he had done the "right thing" in the "developing circumstances".

Meanwhile, Susan Hall, one of the other Tory mayoral hopefuls, said Mr Korski "fought a hard campaign with lots of fresh ideas and I appreciate his contribution to the debate".

"The allegations against him are serious and it is right that they are investigated in the proper way," she added.

"My focus remains on making my own positive case to members and Londoners in this contest."