The former head of the government unit responsible for drawing up Covid-19 restrictions was given a “boozy” leaving party just days before Christmas, it can be disclosed.

The Telegraph has been told that “dozens” of officials from the Cabinet Office’s Covid-19 taskforce attended the event on Dec 17 2020 while the country was still under draconian restrictions.

Those present are alleged to have gathered in the taskforce’s office in 70 Whitehall that evening, where they consumed alcohol and held a party to mark the departure of Kate Josephs, the then director-general.

A source with knowledge of the incident alleged that Simon Case, the Cabinet Secretary, was invited to the event, although the Cabinet Office said “categorically” that he did not attend.

It took place on the same evening that Mr Case’s own staff held a gathering in his private office, and 24 hours before Number 10 staff hosted their own Christmas Party. 

At the time of the event, London had just entered tier three restrictions, with parties banned and people prohibited from mixing indoors with anyone outside their household or support bubble.

On the day of the party, the Government tweeted its official guidance, which stated: “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”.

Ms Josephs, who was awarded the Companion of the Order of the Bath in the Queen’s Birthday honours last June in recognition of her exemplary public service, left Government the following day.

Sue Gray to investigate 

On Friday sources confirmed that the event was now being investigated by Sue Gray as part of her investigation into multiple allegations of lockdown-breaking parties, which are now thought to total 14.

The disclosure is particularly damaging for Boris Johnson because the taskforce is the central body responsible for coordinating the Government’s response to the pandemic. 

The taskforce also plays a key role in drawing up potential measures to control the spread of Covid-19, as well as compiling briefings and papers for ministers to discuss at key Cabinet committees.

The disclosure is likely to raise alarm bells within the Civil Service, with senior Whitehall officials concerned the body is becoming increasingly embroiled in the scandal as more details emerge of officials hosting or participating in events. 

It comes just hours after this newspaper revealed that two parties were held in Downing Street the night before the Queen was pictured sitting alone at the funeral of the Duke of Edinburgh. 

The event was the second of two gatherings that took place in the Cabinet Office that evening.

Just a few dozen metres away, in a separate room, a group of officials working for Mr Case were also taking part in an event in his private office where alcohol and snacks were bought by attendees.

The following evening, on Dec 18, dozens of officials and aides hosted an alleged Christmas party in No 10, during which Boris Johnson’s director of communications gave a thank you speech and handed out awards.