Novelist and TV producer Daisy Goodwin has accused a Conservative mayoral hopeful of groping her 10 years ago.
Ms Goodwin told the Times that in 2013 Daniel Korski sexually assaulted her by putting his hand on her breast during a meeting at 10 Downing Street.
He has denied the allegation “in the strongest possible terms”.
The Conservative Party says it will not investigate the allegations made by Ms Goodwin, creator of ITV drama Victoria, as no formal complaint has been made.
Ms Goodwin said she had met Mr Korski – then a special adviser to David Cameron – to discuss a proposed TV show.
‘View of his crotch’
Ms Goodwin told the Times she met the government special adviser (spad) at a social event and he suggested they meet again.
She said Mr Korski arrived late for their meeting, remarked on her sunglasses and said she looked “like Monica Bellucci, the 50-something Italian actress who had recently made headlines by appearing in a Bond film opposite Daniel Craig as an older woman”.
Ms Goodwin said this felt “awkwardly flirtatious” and “odd”.
She said during the meeting Mr Korski “put his feet on the edge of my chair, leaning back so that I could get a clear view of his crotch”.
“When we both stood up at the end of the meeting and went to the door, the spad stepped towards me and suddenly put his hand on my breast.
“Astonished, I said loudly, ‘Are you really touching my breast?’
“The spad sprang away from me and I left.”
Mr Korski, who left a Conservative Environment Network husting early on Monday evening, wrote on Twitter on Tuesday that the accusations were “baseless”.
He said: “I want to take a moment to address the recent allegation that has been levelled against me.
“I understand that this news may have caused concern, and I want to assure you I categorically deny any wrong-doing.
“Politics can be a rough and challenging business. Unfortunately, in the midst of this demanding environment, this baseless allegation from the past has resurfaced.
“It is disheartening to find myself connected to this allegation after so many years, but I want to unequivocally state that I categorically deny any claim of inappropriate behaviour. I denied when it was alluded to seven years ago and I do so now.
“To be clear – nothing was raised at the time, nothing was raised with me seven years ago when this was alluded to and even now, I’m not aware that there was an official complaint.”
‘Encourage women to come forward’
Conservative Campaign Headquarters said: “The Conservative Party has an established code of conduct and formal processes where complaints can be made in confidence.
“The party considers all complaints made under the code of conduct but does not conduct investigations where the party would not be considered to have primary jurisdiction over another authority.”
Although Downing Street has refused to be drawn on the individual case, or say whether there will be a Cabinet Office investigation into Mr Korski, the prime minister’s official spokesman said Mr Sunak believed No10 was a safe environment for women.
Asked if Mr Sunak thought it was important that allegations of harassment should be investigated, the spokesman said: “Without wanting to be drawn into specifics, I think in any walk of life I think the prime minister would expect that to be the case.”
Ms Goodwin spoke in 2017 about being groped at 10 Downing Street without naming her alleged assailant, however she said she had chosen to identify him now as Mr Korski was running to be the Conservative candidate for the contest to be mayor of London.
She told the BBC on Monday: “I hope that my example will encourage women to come forward – no women should have to put up with this kind of behaviour.”
Mr Korski is one of three candidates shortlisted by the Conservative Party ahead of next year’s election, at which Sadiq Khan will be running for a third term as mayor.
Mr Korski has centred his campaign on improving public services through technology.
Earlier this month he told the BBC he was “a businessman who will put digitalisation at the core of how I improve London”.
Follow BBC London on Facebook, Twitter and Instagram. Send your story ideas to hellobbclondon@bbc.co.uk