SCOTTISH Labour faces an historic electoral wipe-out if it fails to back a final say on Brexit, according to new research which adds to pressure on the party’s ruling body today.

The analysis by Best for Britain and Hope not Hate also predicted the Scottish Tories would lose all their MPs if there was a general election.

It forecast the SNP would win 55 of Scotland’s 59 constituencies, and the LibDems four, while across the UK, Labour would losing 40 per cent of its vote from the 2017 election.

Labour would lose three votes to Remain parties for every one vote lost to the Brexit Party.

The analysis, based on responses from 15,230 respondents in England, Wales and Scotland last month, comes ahead of a key vote by Labour’s Scottish Executive Committee today.

The party leadership is expected to back a confirmatory vote on a Brexit deal, with Remain on the ballot.

The formula does not got far enough for many Remain supporters in the party, as it refers to a Brexit deal which does not yet exist, and may never arrive.

But it goes beyond the previous position of Scottish Labour leader Richard Leonard, which was to pursue a Labour Brexit deal and resist a second referendum.

It would also go further than Jeremy Corbyn, who yesterday said UK Labour was “not at the stage yet” to push for a public vote, an intervention that may yet sway today’s SEC.

The vote was spurred by Scottish Labour coming fifth in last month’s European election, when it fell to 9% of the vote, and lost both its MEPs.

Brexit spokesman Neil Findlay quit the frontbench and announced he was leaving Holyrood in 2021, and Remainer Daniel Johnson stood down as justice spokesperson.

The new analysis said it would be “virtually impossible” for Labour to get a Westminster majority with its current Brexit policy, relying on the LibDems or the SNP to stay in power.

Although UK-wide, Labour would not lose many MPs as the Leave vote would split between the Tories and Brexit party, it would be completely shut out of Scotland for the first time in nearly 100 years, with the Tories wiped out for the first time since 1997.

All six Scottish seats held by Labour and the 13 held by the Tories in that scenario would be gained by the SNP.

Naomi Smith, of the pro-EU Best for Britain group, said: “The Labour leadership now needs to pick a side, and that can start with the SEC voting to become a party of remain.

“It’s obvious which position Labour should take if it wants to be in government, and Richard Leonard can demonstrate leadership on this for the entire UK party.

“This report should also be a wake-up call to internationalist MPs in all parties.

“If a new Conservative leader strikes a deal with Nigel Farage, future generations won’t forgive those internationalist MPs who fail to do the same, and strongly make the case for a final say on Brexit.”

A source close to Mr Leonard said: “Scottish Labour will back a confirmatory vote on any Brexit deal with a Remain option on the ballot paper.

“The Party will wholeheartedly fight for a Remain victory in such a vote, with Richard playing a leading role in the campaign.

“Only Scottish Labour is building a radical platform of investment for our people, communities and public services.”