A HISTORIAN and cross-bench peer has warned that we are in “the most severe constitutional crisis” in our lifetimes – amid Boris Johnson’s partygate scandal.

Expert on government history Peter Hennessy branded the Tory leader a “rogue” Prime Minister.

His remarks came amid talks between the SNP, Labour and LibDems at Westminster about forcing a crunch vote on whether Johnson misled the Commons.

Johnson in December repeatedly told MPs that “no rules were broken” – but has since been fined by the Met Police for breaching Covid-19 rules, along with Chancellor Rishi Sunak.

The National: Chancellor Rishi Sunak was also fined by the Met PoliceChancellor Rishi Sunak was also fined by the Met Police

A vote could take place in Parliament as soon as tomorrow when MPs return from Easter recess.

It would likely see Tory MPs whipped to support the Prime Minister – leaving the Scottish Tories in the Commons who often trade on a perception of distance from Johnson with a choice of either visibly endorsing his actions or otherwise.

Hennessy was made a non-political life peer in 2010 and has been the Attlee Professor of Contemporary British History at Queen Mary University of London since 1992.

The National: Peter Hennessy hit out at Boris JohnsonPeter Hennessy hit out at Boris Johnson

Appearing on BBC Radio 4’s Broadcasting House yesterday, he said: “I think we’re in the most severe constitutional crisis involving a prime minister that I can remember.”

The peer then recounted a diary entry he had written on April 12 – the day that Johnson offered an “apology” but refused to resign.

Hennessy, who is 75 years old, said: “Tuesday the 12th of April, 2022, will be forever remembered as a dark, bleak day for British public and political life.

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“It is the day that Boris Johnson became the great debaser in modern times of decency and public and political life, and of our constitutional conventions – our very system of government.

“The moment was captured on film forever. Just after 6pm, Johnson, in a panelled room at Chequers, clutching a prepared statement which he reads to the cameras for Vicky Young of the BBC, apologises, says he’s paid the fine and refuses to resign.

“He was, he added, speaking in a spirit of openness and humility.

“If there were cocks on the Chequers estate, where all this was going on, they would have crowed at their very loudest at this point, as the Prime Minister sealed his place in British history as the first lawbreaker to have occupied the premiership – an office he has sullied like no other, turning it into an adventure playground for one man’s narcissistic vanity.

“Boris Johnson has broken the law, misled parliament and has, in effect, shredded the ministerial code, which is a crucial part of the spinal cord of the constitution.

The National: Boris Johnson

“And the great weakness of the system is that the Prime Minister, the wrong’un in chief, is the guardian of the code, and with it, the supposed protector of accountability and decency.

“The Queen’s first minister is now beyond doubt a rogue Prime Minister unworthy of her, her parliament, her people and her kingdom.

“I cannot remember a day where I’ve been more fearful for the wellbeing of the constitution.”

He added that Johnson “must have knowingly misled when he said the guidelines were kept throughout”.

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The Prime Minister has claimed he spoke to MPs in “good faith” – and did not “knowingly” mislead.

Johnson is expected to deliver a “regular parliamentary statement” tomorrow reiterating his position.

However, Opposition politicians are considering triggering proceedings that could see Johnson found in contempt of parliament.

The motion would have to be granted by Commons speaker Sir Lindsay Hoyle.

MPs behind the plans are, in part, looking for a way to force Tory MPs to declare their loyalty to Johnson or otherwise ahead of the council elections.