Boris Johnson goes into a new week ready to defend his premiership again as he prepares to insist to MPs there are bigger issues to focus on than the partygate saga.

Despite being fined by the Metropolitan Police for his birthday bash held in the Cabinet room in June 2020, while coronavirus restrictions were in place, the Prime Minister is expected to tell MPs on Tuesday that this should not be the focus of politicians.

Mr Johnson is reported to be preparing to make a statement in the Commons once MPs return to Westminster following the Easter recess.

But it comes after a thinly-veiled reference to standards in politics by one of the Church of England’s most senior clergymen, the Archbishop of York.

Using his Easter sermon on Sunday, Stephen Cottrell urged Britons to ask what sort of country they wanted to live in.

He said: “Do we want to be known for the robustness of our democracy, where those in public life live to the highest standards, and where we can trust those who lead us to behave with integrity and honour?”

The Times reported that Mr Johnson was set to focus on Ukraine, the cost-of-living crisis, and a trip to India which will focus on defence and trade.

As well as addressing MPs in the Chamber, The Times reported Mr Johnson would speak to a meeting of the entire Conservative parliamentary party on Tuesday evening.

Sir Lindsay Hoyle, the Commons Speaker, is also expected to decide if to allow a vote on whether to refer Mr Johnson to the Privileges Committee – which would decide whether he had misled the House over his partygate explanations.

Cabinet minister Jacob Rees-Mogg indicated the defence Mr Johnson may reach for on Sunday.

Speaking to BBC Radio 4’s The World This Weekend programme, he 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.”

But Mr Johnson was also accused over the weekend of not only attending a leaving party for his former communications chief Lee Cain on November 13, 2020, but instigating the do.

Downing Street declined to comment.

On Sunday, crossbench peer and historian Peter Hennessey told BBC Radio 4’s Broadcasting House programme that the country was in “the most severe constitutional crisis involving a prime minister that I can remember, and it goes to the heart of the character of the Prime Minister”.

Reading from his diary entry from Tuesday, when Mr Johnson apologised after receiving his partygate fine, Lord Hennessey said the PM had “shredded the ministerial code” and was “unworthy” of the Queen, “her Parliament, her people and her kingdom”.

Still reading from the entry, he added: “I cannot remember a day where I’ve been more fearful for the wellbeing of the constitution.”

However, Mr Rees-Mogg played down the “constitutional significance” of the ministerial code.

Speaking on BBC Radio 4’s The World This Weekend programme, he said: “The ministerial code is not a legislative part of our constitution, it is a set of guidelines produced by the Prime Minister.”

He said that when Mr Johnson told MPs rules had been followed in No 10 during Covid restrictions: “I think that the Prime Minister spoke to Parliament in good faith.”