He continued: “The party that was put to the Prime Minister on Wednesday happened because an invitation was sent to a hundred people saying ‘let’s have some socially distant drinks in the garden and bring your own booze’. There is simply no comparison.”

The Labour leader called on Mr Johnson to resign for breaking the law and lying about the Downing Street parties.

He said that “industrial-scale partying” had been going on at Downing Street, adding: “I think the facts speak for themselves. I think the Prime Minister broke the law. I think he then lied about what had happened.”

Johnson ‘degraded office of PM’

Sir Keir said Mr Johnson needed to resign as he had “degraded” the office of Prime Minister and “lost all authority” in the country.

Meanwhile, Sir Keir said he hopes that Plan B restrictions will be lifted “as soon as possible”.

He told the BBC: “The sooner we can lift the final restrictions, the better. I think that’s what the whole country want.

He added: “So, if it’s the right thing to lift those restrictions, we will vote to lift those restrictions. But we’ll be led by the science as we always have been, not by the politics of propping up a broken Prime Minister.”

Last week the Opposition leader was branded an “absolute hypocrite” after the photo was highlighted by a senior Tory source.

“Sir Keir has spent the past two months criticising people for doing the exact same thing he’s been doing himself,” the source said. “He is an absolute hypocrite.”