THE SNP are not poised to save Boris Johnson from a backbench revolt over vaccine passports, Ian Blackford has announced.

Reports suggested that the SNP’s contingent of MPs could back the Prime Minister’s plans for Covid certificates if they were brought before Parliament.

At least 40 Tory MPs are expected to rebel, with Labour also opposed to the proposals as they stand.

Blackford tweeted: “The UK Government hasn't published any firm proposals on covid certificates, and the Tory position has been mired in confusion and contradiction.

“On the basis of the information available, SNP MPs would not support Tory plans due to serious concerns over ethics.”

He added: “Depending on the global context, there might be a need to consider means to facilitate international travel. Any such proposals could only be agreed in full consultation with the devolved governments.

“There also remain considerable issues to resolve on equity, ethics and privacy, which the UK government has not addressed. This is a matter of serious concern for the SNP.”

READ MORE: Nicola Sturgeon 'open-minded' on vaccine passports but has 'ethical' concerns

Nicola Sturgeon has said she expects vaccine passports or certification in some form in Scotland and called for a “mature, grown-up debate” about their use.

The First Minister said she was “open-minded” on the issue of vaccine passports but insisted that there needed to be public support and confidence in the idea.

A UK Government review into "Covid status certification" found they could "potentially play a role" in settings such as theatres, nightclubs and mass events, and might also be used in pubs and restaurants to reduce social distancing restrictions.

The prospect of having to show a certificate to access shops or bars has outraged members of the Covid Recovery Group (CRG) of Conservatives, while Labour hit out at the "discriminatory" and "poorly thought-through" proposals.

The use of certificates – which would include vaccination status, test results or evidence of someone having contracted and recovered from Covid-19 – is opposed by at least 40 Conservative MPs.

With Labour's opposition also hardening, along with the SNP raising concerns, the UK Government would face difficulties in getting the measures through the Commons if Johnson pushed them to a vote.

Ministers have ruled out bringing in certification for either the April 12 or May 17 stages of the road map but the documents – either in paper form or on an NHS app – could be introduced later this year.

The Prime Minister suggested that vaccination passports for overseas travel were "going to be a fact of life" because a lot of countries were looking at the possibility.

On the domestic front, he indicated "we are also going to look at the role of a number of signals that you can give that you are not contagious", highlighting the role for mass testing.