PRIME Minister Boris Johnson imposed new coronavirus restrictions for England today, just as his government faced damaging accusations over the breaking of isolation rules in Downing Street last Christmas.

During a televised press conference, the PM confirmed that the country would be moving to “plan B” restrictions in response to Covid-19’s omicron variant.

The decision reintroduces work-from-home guidance from next Monday for those who are able to, extends the requirement to wear face masks indoors from this Friday, and makes the NHS Covid pass – or a negative test – mandatory for entry to certain venues.

But the timing of the announcement was viewed with suspicion in Westminster, as the PM was forced to apologise after footage emerged of senior aides joking about a Downing Street Christmas party during last December’s lockdown.

Allegra Stratton, who was the PM’s spokeswoman, resigned after the clip was leaked, offering “profound apologies” and saying she would “regret those remarks for the rest of my days.”

In the footage, Ms Stratton and adviser Ed Oldfield, along with other aides, were filmed joking about a “fictional” Downing Street party.

A laughing Ms Stratton said: “This fictional party was a business meeting … and it was not socially distanced.”

Mr Johnson has repeatedly insisted that rules were followed in Downing Street since the claims first emerged about the party, reportedly held on December 18 last year.

He said he had ordered an investigation by Cabinet Secretary Simon Case “to establish all the facts and to report back as soon as possible — and it goes without saying that if those rules were broken then there will be disciplinary action for all those involved.”

Labour leader Sir Keir Starmer said the PM’s apology “raises more questions than answers” and that he had been “caught red-handed.”

He added: “Millions of people now think the Prime Minister was taking them for fools, that they were lied to. They are right, aren’t they?”

Scottish Conservative leader Douglas Ross said it was undeniable that there had been some kind of party — and that Mr Johnson should step down if he misled Parliament.

He was just one of several senior Tories to criticise Mr Johnson’s handling of the issue, with former Scottish Conservative leader Ruth Davidson describing it as “pathetic.”

A man whose father died alone in hospital after being admitted on the day of the alleged party said the revelations have left him “crushed.”

Rob Kelleher said his father, 88-year-old Sidney Robert Kelleher, died on January 10 without seeing a member of his family again in person.

“My mam is sitting at home not watching the telly or even having the radio on because she just can’t deal with this,” he said.

“I just feel so lost and angry.”

In the Commons, Labour MP Rosena Allin-Khan questioned how Mr Johnson slept at night.

“Last Christmas while we were in lockdown, millions of people were unable to be with their families,” Dr Allin-Khan said.

“Thousands of people waved through their care home windows at loved ones wishing them a merry Christmas from the side of the road. People died without that last touch from their daughters, their sons, their wives.

“Working in intensive care, I wept behind my mask as three children talking to their dying mother on an iPad begged her to wake up.

“Countless children now growing up without parents while parties were held at No 10.

“This is disgraceful, this is an insult to everyone who followed the rules, it is an insult to everyone who wasn’t allowed to say their final goodbye.”

The Scottish National Party’s Westminster leader Ian Blackford said that if Mr Johnson does not resign, “he must be removed.”

“It is clear that this Prime Minister has lost the support of the public and now even of his own benches,” he said.

New Sage data had earlier suggested that at least 1,000 people a day could need hospital treatment for omicron by the end of the year if restrictions were not introduced.

Leaked minutes of a Sage meeting held on Tuesday backed the need for measures to reduce transmission of the virus and to protect the NHS from “unsustainable pressure.”