THE Tories could be set to "call the SNP’s bluff" and agree to a "surprise" second independence referendum in the winter of next year, unionist sources have told the BBC.

According to a report this morning, there is a “high risk temptation” for some in Whitehall to try and “force a vote on the SNP before they actually want to move, to use the power of surprise”.

Speaking on the Today programme, the BBC’s political editor Laura Kuenssberg said that private polling carried out by the Unionist side was “pretty dreadful”. 

She said there was “a wide spectrum of debates about what to do” about rising support for independence. 

A Survation poll last week became the 12th in a row to show a majority of Scots support independence.

It also suggested the SNP will have win a majority at next May’s Holyrood election.

Last night John Major warned Boris Johnson about the risk of standing in the way of indyref2. He suggested his successor allow a second independence referendum, but only on the condition of holding a third, confirmatory vote after negotiations.

Tory reaction to the speech has suggested that No 10 are unconvinced by the former Tory Prime Minister’s suggestion.

READ MORE: John Major tells Boris Johnson not to rule out a second independence referendum

However, according to the BBC’s sources there has been “some whispering around the place in Westminster about the possibility of essentially trying to call the SNP’s bluff to grant them another referendum, if they get a majority in May, perhaps maybe this time next year”.

Kuenssberg added: “And that's not because anyone in government actually wants to have another referendum or split the UK apart but there is what one source described to me as a very high risk temptation to force a vote on the SNP before they actually want to move, to use the power of surprise.”

However, she added that this proposal had been “rejected in very strong terms by figures who would be involved in actually making such high stakes decisions”.

“I was told, ‘it's insane’ by one source. Someone else said no one credible is making an argument for such a vote. But some involved in those conversations are really worried about the lack of a coherent strong forceful argument to put forward. 

“There is a sense that No 10 would rather it all went away, they've had so much on their plate. 

“It's very clear though that the Prime Minister does not want this to happen. He does not want to allow another agonising constitutional question to dominate the early years of his term in charge, far less to allow for the possibility that having taken the UK out of the EU, which he wanted to do, Boris Johnson then opens the doors to the end of the Union, which he does not want to do”

In a speech to Middle Temple in London on Monday night, Major said “the combination of Brexit – and the unpopularity of our present Westminster Government in Scotland” had increased the likelihood of independence. 

He – wrongly – added: “In law, the Scots require the approval of the Westminster Government before they can legally hold a new independence referendum.

“But refusing one might help the separatist case, by adding to the list of grievances the Scottish National Party exploit with such skill.

“The choice for the UK Government is either to agree the referendum can take place – or to refuse to permit it. Both options come with great risk. But the lessons of Brexit may offer a way ahead. 

“The Westminster Government could agree for an independence referendum to take place, on the basis of two referenda. The first to vote upon the principle of negotiations, and the second upon the outcome of them.

“The purpose of the second referendum would be that Scottish electors would know what they were voting for, and be able to compare it to what they now have. 

“This did not happen with Brexit: had it done so, there may have been no Brexit. Many Scottish voices – and especially business – may support the logic of this: it may focus minds away from a short-term reflex opposition to a perceived English Government, and back to the mutual and long-term virtues of the Union”.

Last week Alister Jack made clear the UK Government would refuse any request for a Section 30 order “for a generation”.

When asked if ministers were ruling out a referendum for the full term of the next Scottish Parliament, even if a pro-independence majority was returned, Jack said “it’s no for a generation”.

Asked to define a generation, he said: “Is it 25 years or is it 40 years? You tell me.

“But it’s certainly not six years, nor 10."