The government's former head of ethics has apologised after receiving a fine from the police for attending a party in the Cabinet Office during lockdown.
Helen MacNamara was reported to have gone to a leaving do for a fellow civil servant on 18 June 2020.
It is one of 12 events being investigated by the police.
The former official said she had "accepted and paid the fixed penalty notice", adding: "I am sorry for the error of judgement I have shown."
Ms MacNamara - who is now the Premier League's director of policy - is the first person to be named as part of the Met Police's investigation into lockdown parties in Downing Street and across Whitehall during Covid lockdowns in 2020 and 2021.
Last week, the force confirmed it had sent out 20 fines so far, with sources telling the BBC some had been given to people who attended a leaving party in Downing Street on 16 April 2021 - the eve of Prince Philip's funeral.
Prime Minister Boris Johnson did not attend either leaving do and has so far not been issued with a fine.
He is believed to have attended at least three of the gatherings being investigated by the police.
Both the force and Downing Street have said they will not publish the names of all those who receive fines, but No 10 said they would make it public if the PM was given one.
The Met launched its investigation into the events that may have breached lockdown rules in January, after allegations about parties surfaced.
An interim report released by senior civil servant Sue Gray into the allegations said there had been "failures of leadership and judgment" by No 10 and the Cabinet Office over the gatherings.
In December, Mr Johnson told the Commons that "all guidance was followed completely in No 10" during periods of lockdown.
Later, when he was revealed to have attended a party in the garden of No 10, he insisted he believed it had been a "work event", and apologised for not sending people home.
The prime minister has been accused of misleading the House of Commons over his remarks - which would break the ministerial code - but No 10 has insisted that "at all times he has set out his understanding of events".
Brexit opportunities minister Jacob Rees-Mogg also defended his boss's comments on Monday, saying Mr Johnson had been given the "wrong information".
He told LBC: "If the prime minister is told information that is incorrect and passes that information on he has made no deliberate attempt to mislead anybody."
But Labour leader Sir Keir Starmer said: "If the PM wants to come to Parliament and tell us that he was repeatedly lied to by his own adviser then let him do that.
"The idea that he had no idea what was going on in his home and his office and only gave answers because he was lied to by his officials is a case he needs to make... I don't think he can."
Ms MacNamara served as director general for propriety and ethics in the Cabinet Office between 2018 and 2020, before becoming deputy cabinet secretary until she left the civil service in 2021.