Boris Johnson has “shredded the ministerial code” by not resigning over partygate, according to a leading historian.
Lord Hennessy said the prime minister had “broken the law and misled parliament” after he was fined by the Metropolitan Police for breaking his own Covid rules.
Johnson, his wife Carrie and chancellor Rishi Sunak were all handed fixed penalty notices for attending a birthday party for the PM in No. 10 in June, 2020.
He has been accused of misleading parliament - a breach of the ministerial code - by telling MPs last December that Covid rules were followed in Downing Street at all times.
Although he has apologised, the prime minister is expected to mount a strong defence of his behaviour when he makes a statement to the Commons on Tuesday.
Speaking to the BBC’s Broadcasting House, Lord Hennessy, who is a crossbench peer, said “we’re in the most severe constitutional crisis involving a prime minister that I can remember”.
He said he had written in his diary “Tuesday 12 April 2022 will be forever remembered as a dark bleak day for public and political life” and went on to describe Johnson as “the great debaser in modern times of decency in public and political life, and of our constitutional conventions”.
“The Queen’s First Minister is now beyond doubt a rogue prime minister, unworthy of her, her Parliament, her people, and her kingdom,” he said.
“I cannot remember a day when I have been more fearful for the well-being of the constitution.
“It’s an assault on not just the decent state of mind which keeps our society open and clean but also on the institutions of the state.
“If he’s not prepared to do the decent thing... why should anybody else behave decently and properly? The whole decency of our public life turns on this question.”
But the PM was defended by Jacob Rees-Mogg, who said he “spoke to Parliament in good faith” when he insisted no rules had been broken.
The cabinet minister said: “I think that when you hear what happened on the party for which he has been fined, many people would think that they were in accordance with the rules, when they were meeting people they were with every day, who happened to wish them a happy birthday, because that was the day it was.
“I think that was a perfectly rational thing to believe. Now the police have decided otherwise and the police have an authority. But he wasn’t thinking something irrational or unreasonable, that that was within the rules.”