Speaking anonymously, three insiders have opened up about a world behind No 10's famous front door where the lockdown rules the country was living by were routinely ignored, socialising was regular, with, they felt, the prime minister's implicit permission.
One staffer describes director of communications Lee Cain's leaving do, the event on 13 November 2020, where the prime minister has been pictured raising a glass, but for which he has not been fined.
Others have been judged to have broken the law for being there and received penalties.
Mr Johnson attended and made a speech to thank Mr Cain, but as the party developed "there were about 30 people, if not more, in a room. Everyone was stood shoulder to shoulder, some people on each other's laps…one or two people."
At the party on the eve of Prince Philip's funeral on 16 April 2021, they portray a "lively event... a general party with people dancing around". The gathering becoming so loud that security guards in the building told them to leave the building and go into the No 10 grounds.
"So everyone grabbed all the drinks, the food, everything, and went into the garden," one source says.
"We all sat around the tables drinking. People stayed the night there."
They now concede what went on was "unforgivable".