UK Labour's deputy leader Angela Rayner has demanded answers from Boris Johnson over reports a "Sexist of the Year" award was handed out at a Christmas party in Number 10 during lockdown.

According to The Sunday Times, the gong was apparently handed out at an illicit gathering in December 2020.

Rayner - who was the subject of a controversial Mail on Sunday story last month alleging she opened and closed her legs to distract Johnson in the Commons - has now written to the Prime Minister to confirm whether or not there was such an award presentation.

If there was, she insists the UK Government must release information on who gave it out, who was nominated for it and why, and who lifted the trophy.

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Her letter states: "It has already been established that there were a number of events in Downing Street that were illegal under the lockdown rules in place at the time, but this raises further questions about the conduct of senior political figures during the course of these events that deserve an urgent response from you.

"You have claimed on the record this week that there is "no place" for sexism in politics, and yet there are now serious and credible allegations in the Sunday Times that sexist behaviour has not only taken place in your own office but has been celebrated and rewarded.

"You are ultimately responsible for the culture and activity that takes place within Downing Street under your administration.

"If true, these allegations are not only at odds with your professed opposition to sexism but set a terrible example and must result in further action.

"Please could you confirm what action will now be taken? Given the seriousness of the new revelations in today's Sunday Times and the serious matters and questions arising, I look forward to your speedy response."

On Good Morning Britain on Monday, Tory MP Michelle Donelan was questioned about the claims by Kate Garraway but said that the reports "had not been substantiated".

She said: "I don't think that report has been substantiated. Anything of that nature is completely wrong, there's no room for any misogyny in our politics.

"If that is true, it shouldn't have taken place but the reports have not been substantiated and we have seen dramatic reforms of Downing Street via the Prime Minister since the incidents have taken place following the recommendations of Sue Gray."

Rayner's letter comes amid growing concern about a culture of misogyny and sexual misconduct at Westminster.

Tory MP Neil Parish resigned over the weekend after he was caught watching pornography in the House of Commons.

Parish said he watched X-rated content twice in Parliament, claiming the first time was accidental but the second was intentional and "a moment of madness". 

It has also emerged 56 MPs are reportedly facing claims of sexual misconduct. At least three Cabinet ministers are thought to be among the group referred to the Independent Complaints and Grievance Scheme over the allegations.