Business minister Paul Scully defended Mr Johnson's conduct as the prime minister prepared to face a second day of grilling by MPs following his Commons apology after he was fined last week for breaking lockdown rules.

The prime minister received a fixed penalty for attending a gathering on his birthday in June 2020 and Downing Street is braced for him to face further fines linked to other events under investigation by police.

Politics Hub: Boris Johnson to face Starmer at PMQs later

Mr Scully told Sky News' Kay Burley: "The prime minister interpreted what he felt was the law, the guidance at the time.

"He took his decision in the heat of the moment but he's accepted he's done wrong, he's accepted he's made a mistake - and he's made a full apology - 30 times yesterday in his statement.

"I don't think anyone can really see that and think that he wasn't contrite."

The comments come hours before Mr Johnson faces Prime Minister's Questions in the Commons where the topic of partygate is again likely to be seized upon by opposition MPs.

On Thursday, Parliament will again focus on the issue as Labour tables a motion to refer the matter of whether the PM broke the ministerial code for an investigation by a parliamentary committee - though Mr Johnson himself is scheduled to be away in India.

That investigation would focus on whether the prime minister knowingly misled the Commons when he initially claimed that no lockdown rules had been broken over partygate but will require the support of Tory MPs to go ahead.

Mr Scully told Sky News that other processes - the Met Police inquiry and civil servant Sue Gray's report - ought to be exhausted "rather than start another strand".

He also said he did not think the prime minister "knowingly" misled Parliament.

When pressed on whether he accepted that the prime minister broke the law, Mr Scully said: "The police have found that.

"The only other way of doing it is to go to court and contest the fixed penalty notice and frankly that's not really the appropriate thing to do."

Labour's deputy leader Angela Rayner reiterated her anger towards the prime minister and urged Tory MPs to act.

She told Sky News: "Nobody is above the law in this country and this prime minister needs to recognise that, his MPs need to reinforce that - because if they don't they undermine our democracy."

Sir Roger Gale, a backbench Tory MP who has long been critical of the PM, told Sky News that he had walked out of a meeting of Conservative colleagues with Mr Johnson on Tuesday evening after three minutes - characterising the tone as displaying "a lot of bluster and pantomime performance".

Despite his views on the prime minister, Sir Roger argues that now is not the right time to replace him given the war raging in Ukraine but said that it may be that if there are more revelations "events are going to overtake that".