LONDON — Boris Johnson is already facing calls to resign over a drinks gathering he admitted to attending in May 2020, as accusation of Downing Street staff holding two leaving parties in No 10 on the eve of the Duke of Edinburgh's funeral emerged.

The Telegraph reported the gatherings were made up of about 30 people drinking alcohol and dancing to music until the early hours of April 17. Restrictions at the time banned indoor mixing between different households.

No 10 said a leaving speech had been given but would not comment when asked if there had been drinking and dancing. Prime Minister Boris Johnson was not at either gathering as he was spending the weekend at his country estate, Chequers.

A spokeswoman confirmed Boris Johnson's former director of communications, James Slack, "gave a farewell speech" to thank colleagues ahead of taking up a new role as deputy editor of newspaper The Sun.

Slack has apologised for the "anger and hurt" caused by the leaving event and acknowledged it "should not have happened at the time that it did".

But he said he could not comment further as it had been referred to senior civil servant Sue Gray as part of her investigation into reported parties at Downing Street and Whitehall.

The latest revelation comes as the prime minister faces anger from his own party over attending a drinks gathering in the Downing Street garden during the first lockdown.

Labour's deputy leader, Angela Rayner, said "the buck stops with the PM" over the "culture and behaviors" inside No 10.

According to the Telegraph, Slack's leaving party coincided with another gathering in the No 10 basement for one of the PM's personal photographers.

The reported events were held at a time when the UK was in a period of national mourning, which ran from April 9 to April 17, following Prince Philip's death.

The Telegraph said staff were sent to a nearby shop with a suitcase, that was brought back "filled with bottles of wine".

During the basement gathering, sources claimed there was a "party atmosphere", with a laptop placed on a photocopier with "music blaring out".

The two parties are then said to have joined together in the No 10 garden and continued past midnight.

At the time, England was under "step two" restrictions that stipulated people could not socialize indoors, except with those from their household or support bubble. People could socialize outdoors in groups of up to six people or two households.

Other restrictions at the time included pubs and restaurants only being allowed to serve customers outside.

A Downing Street spokeswoman said Slack "gave a farewell speech to thank each team for the work they had done to support him, both those who had to be in the office for work and on a screen for those working from home".

But asked about the other party and whether drinking and dancing had taken place, she said No 10 had "nothing further to add".

Rayner said: "The Queen sat alone in mourning like so many did at the time with personal trauma and sacrifice to keep to the rules in the national interest.

"I have no words for the culture and behaviors at No 10 and the buck stops with the PM."

The leader of the Liberal Democrats, Sir Ed Davey, also reiterated calls for the prime minister to resign over the growing list of parties, tweeting: "The Queen sitting alone, mourning the loss of her husband, was the defining image of lockdown.

"Not because she is the Queen, but because she was just another person, mourning alone like too many others. Whilst she mourned, No 10 partied."

Fran Hall, from COVID-19 Bereaved Families for Justice, said: "If your neighbors had behaved like this, you'd have been disgusted. For the people running the country to do it and then lie about it shows a complete disdain for the general public."

This latest report adds to the growing list of alleged parties said to have taken place in Downing Street and other government departments during the pandemic.

But Johnson has faced particular criticism after it emerged he had attended one on May 20, 2020 during the first lockdown.

The prime minister apologized on Wednesday in the House of Commons, saying he had joined staff for 25 minutes to thank them for their hard work. But he said he had "believed implicitly that this was a work event".

On Thursday, backbencher Andrew Bridgen became the fifth Conservative MP to publicly say they had submitted a letter of no confidence in Johnson.

He told BBC Newsnight he had submitted the letter with a "heavy heart", believing there was no sign the revelations about parties in Downing Street during lockdown would end soon.

Bridgen, who backed Johnson in the 2019 Conservative leadership contest, said this was "preventing the government from functioning as normal and that's an untenable position".

A minimum of 54 Conservative MPs must send letters to the 1922 committee of backbench MPs in order to trigger a leadership challenge.

Chris Philp, minister for technology and the digital economy, said it was right to wait for the findings of Gray's investigation. He told Newsnight: "I think the public deserve to have a proper investigation with the full facts." — BBC