Boris Johnson was accused on Monday night of an “utterly outrageous” breach of lockdown rules as a leaked email showed one of his top officials invited more than 100 Downing Street staff to a “bring your own booze” party during the first lockdown. The police are now investigating.

The prime minister is believed to have attended the No 10 garden party on 20 May 2020 along with Carrie Johnson, then his fiancee, after it was advertised by his principal private secretary, Martin Reynolds.

“Hi all, after what has been an incredibly busy period we thought it would be nice to make the most of the lovely weather and have some socially distanced drinks in the No 10 garden this evening. Please join us from 6pm and bring your own booze!” the email seen by ITV News said.