PM Boris Johnson took part in No 10 Christmas quiz last year

Boris Johnson took part in a virtual Christmas quiz in No 10 last year, Downing Street has confirmed.

The Sunday Mirror has published a picture of Mr Johnson at the event, which it said took place on the 15 December – when indoor household mixing was banned in London.

Downing Street said the prime minister “briefly” took part to thank staff for their “hard work” during the pandemic.

Labour’s Angela Rayner said Mr Johnson was “unfit to lead this country”.

“Boris Johnson really believes it’s one rule for him, another for everyone else,” the party’s deputy leader said.

“Despite repeated denials of parties in Number 10, it now transpires that there were numerous parties, gatherings and the prime minister even took part in a festive quiz.”

In the photo, the prime minister is pictured at a desk alongside two colleagues, one wearing tinsel scarf and another apparently in a Santa hat.

London was under Tier Two restrictions at the time, which banned mixing of households indoors – apart from support bubbles – and allowed a maximum of six people to meet outside.

Official guidance said: “Although there are exemptions for work purposes, you must not have a work Christmas lunch or party, where that is a primarily social activity and is not otherwise permitted by the rules in your tier.”

Responding to the photo, a No10 spokesperson said: “This was a virtual quiz. Downing Street staff were often required to be in the office to work on the pandemic response so those who were in the office for work may have attended virtually from their desks.”

A Downing Street source told the BBC the two people in the picture with Mr Johnson were members of his closer staff who had come in to help him with the technology.

Meanwhile, the Department for Work and Pensions has confirmed some of its staff drank alcohol and ate takeaways “late into the evening” on several occasions while Covid restrictions were in place.

It follows a report in the Sunday Mirror alleging that political staff and officials working for minister Therese Coffey frequently drank after work until the early hours of the morning.

It comes a day after 10 Downing Street cancelled its 2021 Christmas party amid growing anger over a different gathering on 18 December last year.

After criticism from opposition parties, the media and his own MPs, the prime minister asked Cabinet Secretary Simon Case to carry out an investigation into the 18 December party earlier this week.

The inquiry will also include finding out what happened at another Downing Street gathering on 27 November last year, and another at the Department for Education on 10 December.

Allegra Stratton quit her post as a government spokesperson on Wednesday after a backlash over a video she appeared in from last December, in which she joked about a Christmas party.

The row over Christmas parties continued to escalate as the government announced new rules in England to tackle the spread of Omicron.

Mr Johnson faces a rebellion from about 60 Conservative MPs when the measures are put to a vote in the Commons next week.

Government sources suggested the introduction of Plan B measures for England will be divided into three separate votes on Tuesday, including one on Covid passes which are opposed by some Tories.

But the measures are expected to become law as Labour is backing the government.

On Saturday, a further 633 Omicron cases were reported – although the real number is estimated to be much higher. Overall, a further 54,073 daily cases were recorded across the UK.

Meanwhile, a report by the London School of Hygiene and Tropical Medicine has suggested the UK will face a substantial wave of Omicron infections in January without further restrictions, beyond Plan B.

It also said the number of deaths could range from 25,000 to 75,000 between now and April.