London police say they are investigating a series of alleged parties at British Prime Minister Boris Johnson's Downing Street residence during COVID-19 lockdown.
The announcement will heap even more pressure on Mr Johnson, who is facing calls to resign from within his own party after he admitted to attending several of the events.
Metropolitan Police Commissioner Cressida Dick said officers were looking into "potential breaches" of lockdown restrictions in Downing Street and across Whitehall – the road where a number of government buildings are located in London – over the last two years.
The investigation was instigated after information was provided to the Met through a separate probe into the events, conducted by the Cabinet Office.
That investigation, led by senior civil servant Sue Gray, is continuing. A Cabinet Office spokesperson confirmed there had been "ongoing contact" with police.
A report from the investigation was due to be released this week. But it is now expected to be delayed until the police investigation is over, which could take several weeks.
Speaking in the House of Commons ahead of a statement on the Ukraine-Russia crisis, Mr Johnson said he welcomed the decision for police to investigate.
"I believe this will help to give the public the clarity it needs, and help to draw a line under matters," he said.
The deputy leader of the opposition Labour Party, Angela Rayner, said Mr Johnson was a "national distraction" and called on him to step down.
"Conservative MPs should stop propping him up and he should finally do the decent thing and resign," she said.
On Monday it was also revealed a birthday party was held for Mr Johnson at Number 10 Downing Street in June 2020, when indoor mixing was banned.
ITV News reported up to 30 people attended the surprise event in the Cabinet Room at Number 10 on the afternoon of June 19, 2020, where a cake was presented to the Prime Minster and his wife Carrie led a singing of happy birthday.
Mr Johnson's office denied a party was held.
"A group of staff working in Number 10 that day gathered briefly in the Cabinet Room after a meeting to wish the Prime Minister a happy birthday," his office told ITV News.
"He was there for less than 10 minutes."
Events hit Johnson's approval rating
The Cabinet Office investigation had already been expanded to include up to 16 alleged gatherings that had taken place in and around Downing Street from the start of the pandemic.
Among them, the one that has caused the most outrage for the public and within Mr Johnson's own Conservative party was a "bring your own booze" event organised by the Prime Minister's own private secretary on May 20, 2020.
An email invitation to the gathering was sent to more than 100 people and Mr Johnson admitted he had attended for around 25 minutes to "thank staff" before returning to his office.
Last week he denied that he knew of the event in advance and claimed that nobody had warned him "it was against the rules".
That response drew condemnation during last Wednesday's Prime Minister's Questions at the House of Commons, with former Brexit minister David Davis telling Mr Johnson it was time to "go".
It has also hit his approval rating, which has seen the Conservatives lagging behind the opposition Labour party in opinion polls.
