Rishi Sunak is said to have been “talked out” of resigning as chancellor after he was fined by the Metropolitan Police for breaking Covid-19 lockdown laws.

He reportedly discussed with his aides whether he should step down over the fixed penalty notice (FPN) given for going to Boris Johnson’s birthday party in July 2020. He previously denied attending any parties.

But Mr Sunak was warned that his resignation may mean that Mr Johnson would have to do the same, as well as damaging his own career, according to a report in The Times.

“He is a very honourable man and feels very badly let down by being dragged into this,” one ally told the newspaper. “It is only natural for him to be considering what this means for him.”

Mr Sunak issued an apology some seven hours after Scotland Yard announced its second round of fines over government gatherings on Tuesday.

“I know people sacrificed a great deal during Covid, and they will find this situation upsetting. I deeply regret the frustration and anger caused and I am sorry,” the chancellor said.

Mr Sunak added that he “respected” the Metropolitan Police’s decision to fine him, though appeared to signal that he felt its application of the law had been “stringent” because he was a high-profile figure.

The PM, his wife and Mr Sunak have paid fines imposed by police over a party held on 19 June 2020 to mark Mr Johnson’s 56th birthday.

Rachel Reeves, the shadow chancellor, said Mr Johnson and Mr Sunak did not seem to understand how “deeply offensive” their lockdown breaches are, as she repeated Labour calls for them both to step down.

Speaking to BBC Radio 4’s Today programme, Ms Reeves said: “Fresh leadership would mean that we will have a government that could concentrate on the issues that we need to focus on as a country.”

Mr Sunak has been under pressure since The Independent first revealed his wife Akshata Murty’s non-domicile tax status, which allowed her to avoid paying UK tax on her overseas income.

Ms Murty has since announced that she will pay UK tax on her overseas income. And Mr Johnson had asked Lord Geidt – at Mr Sunak’s request – to conduct an inquiry into whether the chancellor’s interests have been properly declared.

Lord Frost, the former Brexit minister, backed both Mr Johnson and Mr Sunak to stay in their jobs on Wednesday. Asked about the chancellor’s tax arrangements on LBC, the influential Tory peer said: “I don’t think he did anything wrong.”