LONDON: British police said on Tuesday that 20 fines would be issued over gatherings in Boris Johnson's offices and residence that broke coronavirus lockdown rules, sparking fresh calls for the prime minister to resign.

Police are investigating 12 gatherings held at Downing Street and the Cabinet Office in 2020 and 2021 after an internal inquiry said Johnson's staff enjoyed alcohol-fuelled parties, with the British leader attending some of the events himself.

The police action confirmed for the first time that unprecedented regulations to protect the nation from COVID-19 were broken by officials at the heart of the government that designed them.

Recipients of the fines will not be identified but Downing Street has previously said it will reveal if the prime minister receives one. Police said further fines were still possible as they continued to work through evidence provided to them by the internal investigation.

"We will today initially begin to refer 20 fixed penalty notices to be issued for breaches of Covid-19 regulations," the Metropolitan Police said in a statement. The fines would technically be issued by the ACRO Criminal Records Office.

The statement immediately reignited anger that had threatened to depose Johnson earlier this year, when members of his own party began calling for him to quit and public trust in his leadership plummeted.

"Boris Johnson’s Downing Street has been found guilty of breaking the law," said Angela Rayner, deputy leader of the opposition Labour Party.

"The culture is set from the very top. The buck stops with the Prime Minister, who spent months lying to the British public, which is why he has got to go."

Johnson's office did not immediately comment.

Revelations of the gatherings, many of which took place when people could not attend funerals or say farewell to loved ones dying in hospital due to strict COVID-19 lockdown rules, were first reported in late 2021.

At that time, Johnson said all the rules were followed, though he later apologised to parliament for attending one event, which he said he thought was work related, and then to Queen Elizabeth for another at which staff partied on the eve of her husband's funeral.

Fixed penalty notices are issued to people deemed to have broken COVID-19 rules. The penalty for participating in a gathering of more than 15 people is an 800 pound ($1,048) fine.

The police said they would not confirm which events the fixed penalty notices referred to as it could lead to the identification of the individuals involved.

The police have sent out more than 100 questionnaires as part of the investigation to ask staff to explain their involvement in the gatherings. Johnson was among those who received such a questionnaire.

Police said earlier this month they had begun to interview witnesses as part of their investigation.