The Scottish National Party has said Boris Johnson has lost the trust of the British people and called for him to resign.

Following allegations that a Christmas party was held at Number 10 last year in violation of Covid-19 restrictions, SNP Westminster leader Ian Blackford said the Prime Minister “can no longer lead on the most pressing issue facing these islands” and called on MPs to remove Mr Johnson if he does not resign.

Mr Blackford was speaking at Prime Minister’s Questions, where he and other opposition MPs strongly criticised Mr Johnson’s leadership following leaked footage which showed former Downing Street press secretary Allegra Stratton laughing as she appeared to rehearse answers to questions over a Christmas party.

Mr Blackford said: “Trust and leadership is a matter of life and death. Downing Street wilfully broke the rules and mocked the sacrifices we have all made, shattering the public trust.

“The Prime Minister is responsible for losing the trust of the people. He can no longer lead on the most pressing issue facing these islands.

“The Prime Minister has a duty, the only right and moral choice left to him – it is for his resignation. When can we expect it?”

Mr Johnson replied: “The party opposite and indeed the other party opposite are going to continue to play politics. I am going to get on with the job.”

But the SNP Westminster leader repeated his call for Mr Johnson’s resignation.

Mr Blackford said: “People across these islands have followed the rules even when it meant missing friends and family, missing births, missing funerals, missing the chance to be beside a loved one in their dying moments.

“People have sacrificed at times to the point of breaking, while the UK Government has laughed in their faces.

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

Mr Blackford said “people feel revulsion” over the allegations, and described it as a “moment of moral reckoning”.

“Every member of the Conservative benches must now decide, is this the man to lead these islands when lives are at stake?

“It is time for members in this House to act; if he doesn’t resign, then he must be removed.”

Mr Johnson said: “I thank the right honourable gentleman for his support and vote of confidence but I can tell him I am going to get on with the job.

“I believe that is what is the right thing to do and I think it is very, very sad that, when the public needs to hear clarity from their officials and politicians, the parties opposite are trying to muddy the waters about events or non-events of a year ago.”

Mr Johnson addressed the leaked video earlier in Prime Minister’s Questions, saying he apologised “unreservedly for the offence that it has caused up and down the country and I apologise for the impression that it gives”.

He said he has asked the Cabinet Secretary to establish “all the facts and to report back as soon as possible”, adding: “If those rules were broken then there will be disciplinary action for all those involved.”