The prime minister will face MPs after being issued with a fixed penalty as a result of a police investigation into lockdown breaches in Downing Street and Whitehall in 2020 and 2021.

Mr Johnson is expected to update the House of Commons on the affair as parliament resumes following the Easter break – after new claims about the PM’s involvement in alleged lockdown breaking emerged.

He has already been fined for attending a gathering to celebrate his birthday in June 2020 and over the weekend it was claimed that he instigated a leaving drinks event the following November.

Some Tory MPs have already publicly joined with calls from opposition politicians for Mr Johnson to quit – and Sky News is aware of at least one other who is ready potentially to put in a letter of no-confidence to add to those already sent.

Mr Johnson has said he that he “would set the record straight” over the matter this week.

A key question will be whether he misled parliament as reports of the parties first emerged when he told the Commons that no rules were broken.

As well as addressing MPs in the Commons, Mr Johnson will also reportedly speak to a meeting of the entire Conservative parliamentary party on Tuesday evening.

On Monday, energy minister Greg Hands told Sky News: “The prime minister will have his say in parliament and will outline his version of events and face questions from MPs.”

Mr Hands said he strongly supported the prime minister who he said was “getting on with the job”, citing the COVID-19 vaccination programme and Britain’s support for Ukraine.

But pressed on whether the PM should quit if he receives another lockdown fine, the minister said: “I’m not privy to the police investigation and I think we’ll have to see what the police investigation throws up… I don’t want to prejudge the ongoing police investigation.”

Ministers largely backed the prime minister following last week’s police action – with the exception of justice minister Lord Wolfson, who resigned arguing that what had happened was “inconsistent with the rule of law”.

However support from some backbench MPs has been more equivocal, with some only willing to say that now would not be the right time for the PM to go.

Opposition politicians insist Mr Johnson must step down.

Labour’s shadow policing minister Sarah Jones told Sky News on Monday: “He lied repeatedly, he misled parliament, he’s ripped up the ministerial code… we have more fines potentially to come.

“In parliament, we need to be able to look those MPs in the eye who are defending this prime minister and say every time you defend his lies, you debase the sacrifices that the British people went through.”

Stephen Cottrell, the Archbishop of York, appeared to make reference to the scandal in his Easter sermon over the weekend.

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?

Police have been looking into 12 events in Downing Street and Whitehall in 2020 and 2021 and have so far announced more than 50 fines, with the investigation still ongoing.

Mr Johnson is understood to have been present at six of those gatherings.

The latest claims, aired in the Sunday Times, concern what happened on 13 November 2020 at a leaving drinks event for Number 10 director of communications Lee Cain allegedly instigated by the prime minister – with a photographer taking pictures.

Mr Johnson then reportedly returned to his flat above 11 Downing Street, where a second gathering involving his wife and her friends – with Abba music blaring out – is claimed to have taken place.