THOSE in London who think the threat of Scottish independence is receding are living in a "fool's paradise", Scotland's pre-eminent historian has said.

Professor Sir Tom Devine argued the union remains in greater danger than at any time since the 1745 Jacobite rising. 

He said demographic analysis indicates the Grim Reaper "may be on the side of the SNP's position". 

Sir Tom made the comments during an event at the Edinburgh International Book Festival, in which he appeared alongside Professor Ciaran Martin, a former senior civil servant who played a key role in negotiating the terms of the 2014 independence referendum.

The pair were discussing the question: where next for the United Kingdom?

Mr Martin said the narrative that the danger to the union is receding is "short-term political analysis gone mad".

He said there has been a "sustained, enduring swing" to independence over the course of a decade, while younger Scots back Yes in substantial numbers.

He added: "Now demography is not always destiny and people change their minds, but I think in the historical context these are terrible numbers for the British state.

"The union in 2021 is in better shape than it was in 2020, but apart from that the prospects for it are in worse shape than it any time since, I would venture, the 1760s."

The former constitution director in the Cabinet Office said the UK "remains at much higher risk of dissolution compared to any other rich, stable Western country that I can think of".

However, he said the Scottish Government would likely lose any court battle over a second independence referendum, leading to "stalemate".

READ MORE: SNP would likely lose court battle over Indyref2, says former top civil servant

Sir Tom, who is now professor emeritus at Edinburgh University and famously backed Yes in 2014, said the union is in greater danger than at any time since "Prince Charles Edward Stewart led his Jacobite army across the border to England in 1745". 

He said the two sides of the independence debate are currently in "a state of armistice", but a variety of issues should continue to concern Downing Street, the most important being demographics. 

Analysis shows younger Scots favour independence, Sir Tom said, while men and women now back Yes more or less equally.

He added: "There is that factor to be taken into consideration – that the Grim Reaper may be on the side of the independence analysis, may be on the side of the Scottish National Party's position. 

"We don't know whether those views will change over time as people get older, but that is certainly the position as we speak."

Sir Tom said the Brexit vote was the first time in the history of the union that Scottish opinion on a major issue "was denied".

He said the UK Government is now refusing a referendum, despite acknowledging Scottish self-determination in 2014, and added: "We have now moved quite dramatically, and very swiftly, from a union by consent to a union of enforced law.

"In my opinion, a union of that type cannot stand. It will inevitably be unstable until that particular problem can be sorted out."

The historian said "more rigorous control" of public finances is also coming down the road due to the pandemic, and suggested this could "stir Scottish discontent about the union". 

Elsewhere, he said England and Scotland seem to be going in "radically" different political directions, with "right-wing and semi-nationalist Conservatism" in control in England, while a "moderately left-wing position" is dominant in Scotland.

Sir Tom said England previously treated Scotland with respect and an acceptance that it was a historic nation.

But all the evidence under Boris Johnson's administration suggested Scotland is no longer being treated in this way, he said.

"We're simply not even being allowed to have a vote," he told the book festival.

"This is not about a decision on independence, it's not being allowed to have a vote on one of the great issues of our time."

The historian said he was surprised Scots "are not more outraged by this dramatic transformation, which has literally occurred over the last few years after nearly three centuries of a different and more harmonious regime based on respect and concern for the sensitivities of the other". 

He added: "Remember, 1707 was an agreement between two historic nations. It was not an imposition. What we have now is imposition."

Sir Tom said: "Those in London, and particularly in the political class, who think the problem of the north, the problem of the Scottish question is receding are quite literally living in a fool's paradise."

Mr Martin said that in law, the smooth path to independence "depends entirely on Westminster's acquiescence". 

He said the country is heading for a "stalemate" over the issue but "something has to give eventually". 

The former civil servant suggested it might take another UK general election to "test the will of the Scottish electorate, if not another election after that". 

Mr Martin, a professor at Oxford University’s Blavatnik School of Government, said an important part of the unionist argument will be deciding what sort of union is on offer post-Brexit.