Former deputy chief whip Chris Pincher had his hands "everywhere" at a gay bar in Soho, London, in 2018, according to fresh allegations made to ITV News.
A man who was working in politics at the time alleges that he was groped by the MP on the evening of January 24 that year. He claims that Mr Pincher was drunk and groped his bottom.
The man - who wishes to remain anonymous - also has a handkerchief which he says was given to him by Mr Pincher that night after the pair had spent time together.
Speaking to ITV News, he said: "[Mr Pincher] was pretty tipsy and his hands were everywhere, I felt so uncomfortable knowing that he was an MP."
The alleged incident took place within months of the MP resigning in November 2017 as a whip in Theresa May's government following allegations of sexual misconduct.
The latest claims told to ITV News come on top of a series of other accusations which have been made in recent days after Mr Pincher resigned as Boris Johnson's deputy chief whip amid allegations that he "groped" two men.
The MP for Tamworth, who is under investigation over the latest accusations, told the prime minister he was stepping down after he "drank far too much" at a Tory private members' club and "embarrassed" himself.
Mr Pincher was revealed on Monday to be the subject of other accusations of similar a nature, over alleged behaviour in 2019 which saw a "group of individuals" complain to the Foreign Office permanent secretary.
The complaints led to an investigation within the Foreign Office which upheld the complaint but no disciplinary action was taken.
Number 10 has admitted Prime Minister Johnson was made aware of the investigation, despite previously denying he was aware of any specific allegations against Mr Pincher, but still made him his deputy chief whip in February 2022.
The prime minister's spokesman, explaining the denials, suggested Mr Johnson had forgotten about the 2019 investigation when the most recent allegations were made.
Mr Johnson was made aware of the Foreign Office investigation after deciding to make Mr Pincher his deputy chief whip in this year's reshuffle, deciding it was not appropriate to block the MP's promotion based on resolved matters.
The man who alleges to ITV News that Mr Pincher groped his bottom in Soho in 2018 went on to work for Mr Johnson in Number 10.
He claimed the PM "wanted to give Mr Pincher the chief whip job but was advised to give him deputy to keep a low profile because they knew about his behaviour." "There is no way the prime minister 'forgot' about previous allegations, he was advised not to give him that position or even a senior position at all."
Mr Pincher has generally denied allegations against him however has so far not replied to ITV News's request for a response to these latest accusations.
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The politician, who remains an MP despite intense pressure to quit, is under investigation by Parliament’s Independent Complaints and Grievance Scheme after one of the men he allegedly groped last week submitted a formal complaint.
In a statement at the weekend the former minister said he would co-operate fully with the inquiry and that he is seeking professional medical support following the "stresses of the last few days".
He said he hopes to return to work as an MP "as soon as possible".