Boris Johnson is facing calls to answer allegations he broke Covid rules as reports suggested his attendance at a No 10 staff quiz could be included in an investigation into Downing Street party claims.
Labour said the Prime Minister “might have misled” MPs after he told the Commons he had been given assurances that social distance regulations were not broken by No 10 last year.
The party is demanding that Mr Johnson attend Parliament on Monday to “fess up” about whether he and staff partied and socialised while coronavirus restrictions were imposed on the public.
The Times reported that the online quiz will be included as part of Cabinet Secretary Simon Case’s investigation into potential rule-breaking in Government last year.
The head of the Civil Service is already probing claims of a December Christmas party and November staff leaving do at No 10, as well as festive drinks at the Department for Education.
The Cabinet Office pointed to the terms of reference for Mr Case’s investigation, which state that the inquiry can be widened “where there are credible allegations relating to other gatherings”, when asked by PA news agency whether the quiz would form part of the review.
Downing Street has confirmed Mr Johnson “briefly” attended the “virtual” quiz at the tail end of last year.
An image published by the Sunday Mirror shows the Prime Minister flanked by colleagues, one of whom is draped in tinsel and another wearing a Santa hat, in the No 10 library.
The newspaper quoted a source who claimed that many staff were huddled by computers in their Downing Street offices, conferring on questions and drinking alcohol while the quiz was taking place.
Tier 2 restrictions that London was under on December 15 stated that there could be no mixing of households indoors, apart from support bubbles, and a maximum of six people outside.
Official guidance set out that there should not be work lunches or parties “where that is a primarily social activity” and was not exempted for “work purposes”.
Deputy Labour leader Angela Rayner said: “Despite repeated denials of parties in Number 10, it has now transpired that there were numerous parties, gatherings and the Prime Minister even took part in a festive quiz.
“It appears that Boris Johnson lied to the country and broke the law.
“Boris Johnson and the Conservatives really believe it’s one rule for them, another for everyone else.”
But Education Secretary Nadhim Zahawi defended the Tory Party leader, telling broadcasters on Sunday that the virtual event had respected the rules.
It comes as The Sun said Mr Johnson and his-then fiancee Carrie Johnson had been seen flouting coronavirus lockdown rules during a dinner at a London restaurant in October 2020.
The paper quotes eyewitnesses who said Mr Johnson was seen approaching the tables of other guests while not wearing a face covering, and that the couple did not leave the premises until after the 10pm curfew had passed.
At the time, venues in the capital were subject to strict rules which, as well as the curfew, required diners to wear face coverings when moving around and banned different households mixing.
A No 10 spokeswoman said: “It is categorically untrue to suggest the PM did not adhere to curfew rules in place at the time.
“Any small delay would have been for operational security reasons.”