Writing in a document earlier this month, Tommy Sheppard and Anne McLaughlin admitted a Westminster pact involving Labour “can allow us to explain and promote the progressive case for Scottish independence and help build support for the proposition in Scotland and beyond”.

The paper, entitled ‘The Progressive Alliance: why the SNP needs it’, goes onto state: “The midwife of that process will be our progressive alliance.”

The revelation comes as both Corbyn and SNP leader Nicola Sturgeon prepare to share a stage at the STUC conference in Aviemore.

And it follows reports last week that – despite denials in Edinburgh from Kezia Dugdale – the Labour party is very much preparing to strike a deal with the SNP in a bid to keep the Conservatives out of Downing Street.

Scottish Conservative MSP and candidate for Moray, Douglas Ross, said:

“Nicola Sturgeon wants to use this election to take Scotland back to the division of a second independence referendum.

“Astonishingly, Jeremy Corbyn has said he is ‘absolutely fine’ with her plans.

“We therefore face the clear and present danger of the SNP using Corbyn to push her obsession with independence.

“Now we know exactly why the SNP wants this so-called ‘progressive alliance’.

“As Nicola Sturgeon’s own MPs make clear in this document, they want it to ‘help build support’ for separation and act as the ‘midwife’ for independence.

“That is the truth behind this alliance – it is being proposed by the SNP in order to tear our country in two.

“It is staggering that, despite knowing this, Jeremy Corbyn’s team are still prepared to do a deal with the SNP.

“It’s yet more proof that Corbyn would sell out pro-UK Scots in a heartbeat.”