DOUGLAS Ross has said that Boris Johnson cannot remain as Prime Minister if he knew about Christmas parties in Downing Street and told Parliament he did not.

The Scottish Tory leader said it was "undeniable" that some sort of party had taken place last December after a video appeared to show Downing Street aides joking about it.

The leaked video of a mock press conference showing the PM's former press secretary Allegra Stratton last year rehearsing answers where she joked about a "cheese and wine" night and said that there was no "social distancing" at what she joked was a "business meeting".

At Prime Minister's Questions, Boris Jonhson faced calls to come clean over what he knew about the incident from Labour leader Keir Starmer and a call to resign from SNP Westminster leader Ian Blackford.

Ross had said that he had "confidence" in Johnson, but also made it clear that the PM "cannot continue" in his role if he was found to have misled the Commons.

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Ross told Sky News: “If [Johnson] knew there was a party, if he knew it took place, then he cannot come to the House of Commons and say there was no party.

“That would be a very serious allegation if that were to be the outcome of the inquiry, and we’d have to see the outcome of the inquiry before we speculate on that.

“But anyone who says there wasn’t a party, but knew about it and said in Parliament there was no party has misled Parliament.

“That is a serious charge and you cannot continue in the highest office in the land if you’ve done that.

“If the inquiry said that this time last year he was aware of a party being organised and he knew about a party, that’s a totally different picture and we cannot have the Prime Minister or any member of any Parliament coming to the chamber saying one thing when they know the exact opposite.”

In an interview in Holyrood earlier, Ross said: "Clearly what we have seen over the last 12 hours or so with the video emerging, there are serious questions that need to be answered.

"Now looking at what I have seen, there was a party of sorts.

"I don’t think you can get away from that, and there are questions to be answered on why that was allowed as it was absolutely against the guidance this time last year." 

Ross acknowledged that the Prime Minister said there was no party at Downing Street, but said: "That's why I think there are serious questions to be answered around what happened this time last year and what has happened in the last week as the Prime Minister has been answering questions in the House of Commons.

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"There was a party of sorts. I wasn’t involved, I wasn’t invited, I wasn’t there, but just look at what we have seen since then – there was a party of sorts and that was against the guidance last year."

When asked if he trusted the Prime Minister, Ross said he did, adding: "I have confidence in the Prime Minster of the United Kingdom.

"But when he made statements last week, they seem to be very different to the statements he is making this week, and the video evidence that has emerged since then.

"That’s a really serious issue for everyone involved in whatever happened at Downing Street last December."

The SNP and Scottish Greens branded Ross's continuing support for Johnson as “utterly pathetic”. 

SNP MSP Neil Gray said: "The Scottish Tories’ response to this scandal has been utterly pathetic. It’s frankly outrageous that Douglas Ross now admits that Boris Johnson has lied about the party at Downing Street, but still thinks he is the right man to be Prime Minister.

“Boris Johnson still has some very serious questions to answer and Douglas Ross’s flimsy attempts to distance himself from his own party, and the man he backed to be Prime Minister, just won’t cut it with the public.

“Instead of seeming more interested in saving the future of his Scottish Tory branch office than sticking up for decency and integrity in politics, Douglas Ross should find a backbone and join the SNP in calling on Boris Johnson to resign."

Commenting, Scottish Greens MSP Gillian Mackay said: “Douglas Ross’ refusal to withdraw his support for Boris Johnson is utterly pathetic. 

READ MORE: PMQs: Outrage as Boris Johnson tries to duck responsibility over Christmas party

“The behaviour of Boris Johnson and his government continues to be utterly appalling. At a time of national crisis not only did those in his inner circle breach the very rules they had set down for the public, they’ve continually lied about it, and now footage shows them laughing about it while planning their excuses. 

“This is not a laughing matter to the thousands of us who have lost a loved one during the pandemic, or to all those who were separated from family and friends because they followed the rules. Johnson’s time as Prime Minister will forever be tainted by lies, sleaze and corruption. It is time for him to resign and bring an end to this whole sorry episode.” 

Earlier, former Scottish Conservatives leader Ruth Davidson, now a member of the House of Lords, launched an attack on Johnson over the saga.

Baroness Davidson said the party, and subsequent attempts by No.10 to explain away the event on December 18 last year, were not "remotely defensible".

She tweeted: "None of this is remotely defensible. Not having busy, boozy not-parties while others were sticking to the rules, unable to visit ill or dying loved ones. Nor flat-out denying things that are easily provable. Not taking the public for fools.

"And today's 'we'll investigate what we've spent a week saying didn't happen and discipline staff for rules we continue to say weren't broken' was pathetic.

"As a Tory, I was brought up to believe in playing with a straight bat. Believe me, colleagues are furious at this, too."

PMQs saw Johnson blame his own staff for the reported lockdown breaches as he announced that the Cabinet Secretary, Simon Case, will “establish all the facts and to report back as soon as possible”. Johnson said that there would “be disciplinary action for all those involved”.

Johnson was reported to have given a speech at a “leaving do” party allegedly held on November 27. A staff party was said to have been held on December 18, while reports of a third gathering earlier in November were also raised at PMQs.

A source told The Mirror that “many social gatherings” had been held on Downing Street while the general public faced strict Covid restrictions.

Journalist Adam Bienkov reported that Johnson's spokesman said the Cabinet Secretary will only investigate the alleged Downing Street party on December 18, which the Prime Minister did not attend, and not any other party, including the one he reportedly did attend.