BORIS Johnson must resign if he has broken lockdown rules, Douglas Ross has said.

The Scottish Tory leader called on the Prime Minister to answer the “very simple question” of whether or not he attended a “bring your own booze” party in the Downing Street garden during the first lockdown in May 2020.

Ross’s remarks came after multiple calls for Boris Johnson to resign, including from SNP Westminster leader Ian Blackford who said if he won’t, then the Tory party should “force” him to stand down.

READ MORE: WATCH: First Minister gives verdict on Boris Johnson Number 10 garden party

Speaking on Sky News, Ross said that the Prime Minister could easily confirm whether he not attended the party without impacting on civil servant Sue Gray’s investigation.

Gray is currently investigating claims of Christmas parties held at Number 10, and now the most recent allegations.

Ross said: “It’s not pre-judging Sue Gray’s inquiry to tell the public, for the Prime Minister to come forward and say if he was at the party or not.

“That’s a crucial question that won’t in any way undermine Sue Gray’s investigation, it will let the public know right now if he was there or not, and it’s a crucial question that shouldn’t wait until Prime Minister’s questions tomorrow, we should be able to hear the answer right now.”

Asked if he has confidence in the Prime Minister, Ross said: “If he’s followed the guidance that his government set for everyone else, then yes.

“If he’s not, if he’s breached his own guidance, if he’s not been truthful then that is an extremely important issue and I’ve said previously if the Prime Minister has misled parliament he should resign.”

Asked why the Prime Minister was refusing to say if he attended the gathering or not, Ross said that would have to be put to Johnson.

Ross added: “You’d have to put that to the Prime Minister, I can’t understand why you wouldn’t if there’s nothing to hide here.

READ MORE: First Minister announces easing of Covid-19 restrictions in Scotland

“If there’s no issue, then just answer the question, and if there is then that is an acceptance that he breached guidance he and his government put in place.

“This is guidance that stopped people going to family members funerals, that stopped people grieving together, it meant doctors and nurses were working flat out to get this virus under control and people across the country were following some of the strictest guidance we’ve ever seen.

"And if the Prime Minister and others within Number 10 breached that guidance, while earlier that afternoon a Cabinet office minister told them what they were expected to do, yet out the back of Number 10 people were enjoying sunshine in the garden, then that is utterly despicable.”

The National:

It comes as Ross (pictured) was urged to submit a letter of no confidence in Johnson.

Scottish LibDem leader Alex Cole-Hamilton said his Tory counterpart must now act “because the Prime Minister needs to be removed”.

His comments came as former Scottish Tory leader, Baroness Davidson, said “what tf (the f***) were any of these people thinking” regarding those who attended the party in the garden behind No 10.

READ MORE: Presiding Officer issues warning over Covid restriction media 'leak'

Scottish Health Secretary, Humza Yousaf, meanwhile, accused the PM of “mocking” those who lost loved ones to the virus, as he called for Johnson to resign, saying he has “no moral authority to lead”.

Police are now in contact with the Cabinet Office over claims a senior aide to the Prime Minister organised a “bring your own booze” party in May 2020.

Martin Reynolds, the Prime Minister’s principal private secretary, sent an email to more than 100 Downing Street employees inviting them to “make the most of the lovely weather” in the garden.

At the time, strict coronavirus restrictions banning groups from meeting socially outdoors were in place.