Helen MacNamara said she has paid the fine she was handed in connection with a leaving party held in the Cabinet Office on June 18 2020 to mark the departure of a private secretary.

She said in a statement: "I am sorry for the error of judgement I have shown. I have accepted and paid the fixed penalty notice."

Read more: All you need to know about the Met's partygate investigation

Ms MacNamara was the government's director general for propriety and ethics from 2018 to 2020. She now works for the Premier League where she is director of policy and corporate affairs.

The Premier League declined to comment.

'Raucous' karaoke party

Last week the Metropolitan Police announced 20 fines in relation to an investigation into alleged lockdown-breaking parties in Downing Street and Whitehall in 2020 and 2021.

Ms MacNamara is the first person to confirm they have paid a penalty in relation to the investigation.

The Telegraph reported that the fine was in relation to a "raucous" karaoke party at which there was a drunken brawl.

The event has previously been reported to have been attended by about 20 people including - briefly - Sir Mark Sedwill, then cabinet secretary and head of the civil service.

Fines are now understood to have been issued for that gathering as well as events in Downing Street on the night before the Duke of Edinburgh's funeral in April last year.

The Met Police itself is not naming individuals subject to fines.

But Downing Street has said that it will reveal if the prime minister, or cabinet secretary Simon Case, are among them.

The PM, as well as chancellor Rishi Sunak, were among 100 individuals who were sent formal legal questionnaires related to the investigation.

Welsh secretary Simon Hart has brushed off the suggestion that Boris Johnson ought to resign if he is fined, telling Sky News "the world has moved on a considerable distance".

Most of his constituents "want an apology, but they don't want a resignation", Mr Hart said.

Meanwhile, Brexit minister Jacob Rees-Mogg has refused to apologise for calling the partygate scandal "fluff", telling LBC it is "not the most important issue in the world".

Labour leader Sir Keir Starmer said the general public have "a right to know" which senior Downing Street officials have received fines.

"They are taking the public for fools yet again", he told reporters.

Boris Johnson has refused to admit that "criminality" took place in Downing Street despite the issuing of the fines though two Cabinet ministers - Dominic Raab and Anne-Marie Trevelyan - have conceded that laws were broken.