No 10 officials say party attended by Johnson so cramped people sat on each other’s laps

Hail falls as a police officer stands guard outside 10 Downing Street in London on Tuesday. Photograph: Matt Dunham/AP

Partygoers in Downing Street were so cramped together at a leaving do attended by Boris Johnson that some were forced to sit on each other’s laps, it has been alleged.

No 10 officials speaking anonymously to BBC Panorama said they sometimes arrived at work to find bins overflowing with empty bottles from parties the night before and security guards who tried to stop one illegal gathering taking place were laughed at.