Boris Johnson pictured hosting Downing Street virtual Christmas quiz last year

In the photo, Johnson is pictured on a screen, where he is seen in his office sitting close to two other people, reading out questions, according to The Mirror. CNN hasn’t independently verified the details about the quiz party, which the Mirror says took place on December 15. A Downing Street spokesperson said it was a “virtual quiz” and that Johnson “briefly took part virtually” to thank staff. While the photo shows Johnson with only two others, a source told the Mirror that “many staff huddled by computers, conferring on questions and knocking back fizz, wine and beer,” a claim CNN hasn’t independently verified.According to official guidance at the time, “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.”London was under Tier 2 restrictions at the time of the quiz, which said there should be no mixing of households indoors, apart from so-called support bubbles, and a maximum of six people outside.An internal investigation led by Johnson’s Cabinet Secretary, the UK’s most senior civil servant, is already underway into three events from last year: an alleged party in Downing Street on November 27; a gathering at the Department for Education on December 10; and an alleged party in No. 10 on December 18.After speaking to multiple officials, CNN has established that Angela Rayner, deputy leader of the opposition Labour Party, tweeted that Johnson had “presided over a culture of disregarding the rules at the heart of government.”She added: “Despite repeated denials, it now transpires that there were numerous parties, gatherings and the Prime Minister even took part in a festive quiz.”The Labour Party press office tweeted that on December 15 last year, Starmer had written to Johnson “calling on him to urgently convene COBRA to discuss the worsening Covid situation.” The UK government’s Cobra committee is a cross-departmental group that can be convened in situations of national emergency.”Now we know that instead, the PM hosted a Covid rule-breaching Christmas quiz that evening,” the Labour Party tweet continued.Johnson faced fierce criticism Wednesday after a leaked video recording obtained by CNN affiliate ITV News showed senior Downing Street staff joking about an alleged Christmas party on December 18 last year. On December 17, the government had sent a tweet warning “you must not have a work Christmas lunch or party, where that is a primarily social activity.” Johnson responded to the allegations, telling the House of Commons on Wednesday “I was furious to see that clip”, adding, “I have been repeatedly assured since these allegations emerged that there was no party and that no Covid rules were broken.”Fresh claims emerged Thursday and Friday. Jack Doyle, then deputy head of communications and now Johnson’s most important press chief, addressed a gathering of “up to 50 people” at the December 18 party and gave out jokey award certificates to members of staff, CNN’s affiliate ITV News reported on Thursday. Downing Street and Doyle both declined to comment to CNN while “there is an ongoing review.”CNN’s Laura Smith-Spark wrote from London, while Sugan Pokharel reported from Atlanta and George Engels from London. CNN’s Luke McGee and Sarah Dean contributed to this report.