LONDON (Reuters) -A senior British minister said on Wednesday that Prime Minister Boris Johnson did not set out to break COVID laws with malice and is mortified after he was fined by police for attending a gathering during lockdown, as calls mounted for Johnson to quit.

Johnson, his wife Carrie and finance minister Rishi Sunak were fined on Tuesday for breaching laws the government imposed to curb COVID-19, drawing a wave of condemnation, including from the families of those who died alone during the pandemic.

Senior ministers have rallied round Johnson while a number of previous critics in his Conservative Party have said now was not the time for a change in leadership given the crisis in Ukraine.

However, David Wolfson, a junior justice minister, did resign on Wednesday, saying “recent disclosures lead to the inevitable conclusion that there was repeated rule-breaking, and breaches of the criminal law”.

The prime minister initially told parliament that no parties took place. But police are investigating 12 gatherings after an internal inquiry found his staff had enjoyed alcohol-fuelled parties when social mixing was all but banned in the country.

Johnson has since said he attended some of the events, raising the prospect that he could face further fines. He said on Tuesday that it had not occurred to him that he was in breach of the rules, rejecting calls for his resignation.

“I’m not saying that the prime minister isn’t a flawed individual. We’re all flawed in different ways,” transport minister Grant Shapps told Sky News. “The question is did somebody set out to do these things with malice?”

“The prime minister is mortified about it, but I think there’s a big job for him to get on and do on behalf of the British people, on behalf of the world fighting this cruel war.”

The revelations about boozy Downing Street parties provoked resignation calls from Conservative lawmakers earlier this year. However, that pressure largely abated with the war in Ukraine.

Johnson won a landslide election in 2019 on a promise to complete Britain’s exit from the European Union, but his premiership has been marked by a series of dramatic events, from suspending parliament over a Brexit impasse and his own experience of COVID.

His fine is believed to represent the first time a British leader has been found to have broken the law while in office.

Sunak, a former banker who became chancellor on the eve of the pandemic, took seven hours to release a statement in which he apologised, prompting a report in the Times newspaper that he had considered quitting.

One lawmaker in Johnson’s Conservative Party said on Wednesday that the prime minister should go. “I don’t think the PM can survive or should survive breaking the rules he put in place,” Nigel Mills told the BBC. “He’s been fined, I don’t think his position is tenable.”

(Reporting by Kate Holton, Michael Holden and Muvija M; Editing by Hugh Lawson and Elaine Hardcastle)