The former Downing Street adviser released a lengthy statement on Tuesday after the allegation emerged on Monday evening.

TV producer and screenwriter Daisy Goodwin alleged in an article for The Times that she was "groped" by Mr Korski a decade ago, when he was working for then-prime minister David Cameron.

Politics live: Senior Tory says Rwanda plan is 'very difficult to justify'

In a statement posted on social media, Mr Korski said that "politics can be a rough and challenging business", and that "unfortunately, in the midst of this demanding environment, this baseless allegation from the past has resurfaced".

He made no indication he would step aside from the three-person race to run as the Tory candidate in next year's mayoral election.

Health Secretary Steve Barclay told broadcasters this afternoon that he understood no formal complaint has been made against Mr Korski, meaning the Conservative Party cannot start an investigation.

He added that it was "right" Mr Korski had put out a statement.

Sky News understands that Tory MP and education minister Robert Halfon has paused his support for Mr Korski's bid to stand as London mayor in the wake of the allegation.

Mr Korski said: "I know that simply denying such allegations may not be enough to alleviate the concerns and doubts that might arise in your minds. I firmly believe in the importance of empathy, respect, and the wellbeing of every individual within society.

"I am - and have always been - committed to fostering an environment where everybody feels valued, heard and supported."

He added: "As a father I am especially committed to making sure everyone feels safe on the streets of London.

"To those who have been affected by any form of misconduct or harassment, let me assure you that I stand firmly against such behaviour. I am committed to fostering an environment where everyone feels valued, heard, and supported.

"I am grateful for each and every one of you, for your continued support."

Speaking before the latest statement, one senior Conservative who had been backing Mr Korski told Sky News: "This feels unsustainable, and if I were advising him, I would say pull out of the race, and quickly."

But another Tory MP said "this is not the Daniel I know, I can't believe he would do this", and hoped he would come out fighting.

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.