On Wednesday, the Conservatives admitted an event organised by Mr Bailey’s mayoral campaign took place in the party’s Westminster headquarters on December 14, 2020, at which time London was in Tier 2 lockdown.

Under Tier 2 rules, household mixing was banned except for within support bubbles while no more than six people could meet outdoors.

Mr Bailey, who lost out on becoming Mayor of London in May this year, is now facing calls from City Hall’s Labour group to step down from his position as chair of the police and crime committee.

Labour London Assembly Member Leonie Cooper on Thursday sent a letter to Mr Bailey calling for him to clarify whether he attended the party himself.

In the letter, Ms Cooper said Mr Bailey’s position as chair of the police and crime committee was “untenable” and called on him to step down “until the necessary enquiries have seen completion”.

The City Hall Conservatives have been approached for a response.

A Conservative Party spokesperson on Wednesday revealed four members of Mr Bailey’s campaign team were disciplined following the “unauthorised social gathering” in December of last year which was described as “raucous”.

The revelation has added to the mounting pressure on the Government amid accusations several parties were held throughout December last year while thousands were dying from Covid and most of the country was in some form of lockdown.

Former Downing Street press secretary Allegra Stratton became the first casualty of the scandal on Wednesday.

She stepped down from her role as a Government adviser following the release of a video leak showed her joking about holding a Christmas party.

Despite calls from Labour for police to investigate a breach of the law at the alleged December 18 party at Downing Street, Scotland Yard has said it will not open an investigation due to “an absence of evidence”.