THE rule of Charles III may weaken Scots’ commitment to the Union, according to the royal biographer Clive Irving.

“The Queen held everything ­together,” he said. “Having been on the throne for so long, she ­represented a degree and continuity that can’t be replicated.”

The author of The Last Queen also predicted the SNP’s current ­commitment to the monarchy will “expire” with the Queen’s death, ­according to Time Magazine.

Recent polls have found that only 52% of Scots think Charles will be a good king, compared with 75% who thought the Queen performed her role well.

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Constitutional expert W Elliot ­Bulmer told the Sunday National that Charles was in a difficult position as the Union is “pretty much dead in the water”.

He said the death of Queen ­Elizabeth I and II, had removed any remaining certainty about the ­constitution of the UK.

“Now in a sense everything is up for grabs and I think what it does in terms of the Union is that it breaks the emotional link between the Britain as it is today – which quite frankly is a mess – and the Britain that was, which may have had its problems but there were also quite a lot of redeeming virtues about it,” said Bulmer.

“I think there is an older class or generation who identified with the Queen and her values. It connected them to a Britain they grew up in that they had respect for and they felt was respected in the world. That is on a shoogly peg now. That is really falling apart.”

With the link gone, the ­“weakness” of the UK’s so-called unwritten ­constitution is exposed and although Charles may have a wealth of experience in other roles he has become king at an “incredibly difficult” time with a Prime Minister who is also in a “difficult” position.

“Liz Truss does not have the ­support of her parliamentary party and has stepped on an ideological course which is going to make ­Margaret Thatcher look like a ­moderate,”

said Bulmer.

“This is all in the midst of a ­situation where the assumptions on which our institutions are based – the rules of fair play, not pushing to the extremes in terms of what you can get away with because it is not cricket – all of that has gone.”

Bulmer said this meant Charles was now king of a state in transition but it presented him with an opportunity to preserve the monarchy in a more modern way rather than let the state fail catastrophically when he is its symbolic head.

This would mean he would have to recognise that constitutional change is on the horizon and try to make it work for him.

“If he were clever he would say the way that it has gone up till now is not sustainable and we need to get this sorted out,” said Bulmer.

“That might be a reformed UK with a modern constitution, or it might mean post-Union states. There is nothing to be ashamed of in ­being King of Scots under a modern, ­democratic, independent Scottish constitution based on the sovereignty of the people that puts human rights at its core.

“There is nothing wrong with that. The King of Sweden does it, the King of the Netherlands does it and you still get the palaces and carriages and all of that but what you don’t have is perhaps the same theoretical ­sovereignty. You give that up and ­rebrand yourself as first King of Scots for 300 years.

“He loves Scotland and there is no reason why he could not cultivate that and say, ‘my mother was Queen of the UK but I am going to be king of several kingdoms that are united in different ways’.

“There is nothing within the ­royal tradition that prevents people ­becoming independent and from him going from being the King of the UK to the King of Scots and King of ­England or whatever.”

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Pointing out that the SNP had always had republicans within the party but had never been a formally republican party, Bulmer said he thought Scotland would be willing to accept the crown under those terms.

“People are not necessarily ­opposed to the monarchy – what they are ­opposed to is the British state that the monarchy represents,” he said.

Bulmer added that monarchies tended to collapse when they became complicit in authoritarian regimes.

“Modern monarchies survive when they are the figureheads of a democratic state. If you look at the kings of Italy they sided with Mussolini as they thought it was probably the path of least resistance but they got kicked out in the end,” Bulmer said.