Boris Johnson attended a birthday party thrown in his honour in Downing Street during the first Covid lockdown, despite social gatherings indoors being banned.

The event took place around 2pm on June 19 2020, with a birthday cake presented to the Prime Minister and attendees singing “happy birthday”, according to ITV News.

Carrie Johnson, the Prime Minister’s wife, and Lulu Lytle, the interior designer redecorating the Johnsons’ Downing Street flat, were both reportedly in attendance.

A Number 10 spokesman confirmed that Mr Johnson had attended the event but insisted the Prime Minister was there for less than 10 minutes and that staff gathered “briefly” for the event.

At the time, social gatherings indoors were barred under the Government’s Covid rules and people were only allowed to meet outside in groups of up to six. Pubs and restaurants were shut.

Sir Keir Starmer, the Labour leader, said the revelation showed Mr Johnson “believes that the rules that he made don’t apply to him”.

But Nadine Dorries, the Culture Secretary and loyal ally of Mr Johnson, questioned whether having cake in the office for 10 minutes really amounted to a “party”.

Fuelling the political backlash was a letter Mr Johnson wrote three months earlier praising a girl called Josephine for cancelling her birthday party due to coronavirus guidance.

“Josephine sets a great example to us all by postponing her birthday party until we have sent coronavirus packing,” Mr Johnson tweeted on March 21 2020.