(AFP) - London police said Thursday they had issued more than 50 additional fines over a "Partygate" scandal rocking Prime Minister Boris Johnson's government.

The Metropolitan Police said its investigation into the lockdown parties had "made more than 100 referrals for fixed penalty notices".

In its last update on April 12, the Met said "over 50" fines had been issued. They included Johnson, his wife Carrie and finance minister Rishi Sunak.

The government said they were fined for a gathering in Downing Street marking the prime minister's birthday in June 2020.

Johnson has apologised for the breach of Covid regulations, but refused demands to resign after becoming the first UK leader to be found to have broken the law while in office.

He has not been issued a further fine, sources said after the Met's latest statement.

But the police said their investigation into other alleged breaches was continuing.

Johnson also faces an investigation by a parliamentary committee into his past denials to the House of Commons of lockdown lawbreaking.

The parties have fuelled widespread public anger against the ruling Conservatives, who suffered a drubbing in recent local elections.

The main opposition Labour party's leader, Keir Starmer, on Monday promised to step down if police in northeast England fine him for his own alleged breach of coronavirus laws during a campaign meeting.

The gathering took place in Durham in April last year, with a video later emerging of Starmer drinking beer and eating a takeaway meal inside an office with party colleagues.

© Agence France-Presse