A former Whitehall ethics chief has apologised for an "error of judgement" after being fined by Partygate police over a lockdown karaoke bash.
Helen MacNamara became the first person to publicly apologise for receiving a Partygate fine for attending law-breaking parties in Downing Street and Whitehall during the pandemic.
The ex-senior civil servant was handed a £50 fixed penalty notice on Friday by police over a raucous leaving do at the Cabinet Office on June 18 2020, which resulted in a drunken brawl.
Partygoers used a karaoke machine at the bash for departing No10 official Hannah Young, despite singing and indoor gatherings being banned at the time.
In a statement, Ms MacNamara said: "I am sorry for the error of judgement I have shown. I have accepted and paid the fixed penalty notice."
Ms MacNamara was the director general of propriety and ethics in the Cabinet Office from 2018 to 2020, where she led the investigation into bullying allegations against Home Secretary Priti Patel.
She became deputy cabinet secretary in March 2020, before leaving Government to work for the Premier League last year.
The Metropolitan Police issued 20 fines on Friday as part of the first wave of penalties for the Partygate scandal.
Detectives are investigating 12 lockdown-flouting gatherings in Downing Street and Whitehall, including six events Boris Johnson is believed to have attended.
The Prime Minister has not yet been issued with a fixed penalty notice but No10 has promised to confirm if the PM and civil service chief Simon Case are handed fines.
Scotland Yard will not name those given fines, which is argues is standard practice for offences of this kind.
But pressure is mounting on No10 to come clean if senior figures were found to have flouted the rules.
Labour leader Keir Starmer called for the names of all senior officials fined for Downing Street parties to be made public and accused the Government of "taking the public for fools yet again".
He said: "I think it is very important that the Prime Minister makes sure that all those who are given fines, certainly in senior positions, are named.
"We seem to be going through this process where instant by instant, fines are coming out but the public are being left in the dark.
"The public complied with the rules. They are entitled to know who didn't comply with the rules and what is going on."
Mr Starmer said the PM needed to state if he was lied to by his officials about what was going on in Downing Street, after top Tory Jacob Rees-Mogg tried to claim Mr Johnson had not misled Parliament as he was given the wrong information.
Mr Johnson told MPs last year that no rules were broken - a line repeated by Downing Street.
But the PM has already admitted to attending one of the parties police are investigating.
Mr Johnson accepted he had briefly gone to a BYOB garden party in Downing Street in May 2020 but insisted he believed it was a work event.
His defence is believed to centre on the fact that Downing Street is both his home and his workplace.
