Ros Atkins on... the No 10 Christmas party denials

The prime minister's spokesperson has insisted "there was not a party" at 10 Downing Street last December, and the government has said no Covid guidelines were broken.

But a source has told the BBC that "several dozen" people attended a party on 18 December last year.

Watch as Ros Atkins investigates the gap between government assurances and available evidence.

Produced by Michael Cox