SIR Tom Devine, the leading historian, has claimed the UK is a "failed state," as he predicted the SNP would continue to thrive in an independent Scotland.

The Edinburgh University professor argued the "inept" governance of the UK was a key reason leading to Thursday's vote on independence.

In a lecture at Glasgow University last night he also broke his self-imposed ban on predictions - he maintains "the future is not my subject" - by anticipating continued success for the SNP and the emergence of a strong, centre-right party if Scotland leaves the UK.

The academic and author of The Scottish Nation 1700-2000 ended speculation about his own voting intentions last month by declaring his support for independence.

Delivering a public ­Stevenson Trust lecture, he insisted he was not a nationalist but added: "My interest in what is happening at the moment is because I think the governance of the United Kingdom is now inept, ­inadequate, and we are now almost in the position of a failed state as far as governance is concerned."

He declined to predict the outcome of the referendum but believed at 45 per cent of voters would back independence.

He added: "Who knows what will happen? But what is absolutely plain is the voting will result in a very narrow majority for either side."

Answering questions from the audience, many of whom had to watch on TV screens from an adjoining lecture hall, he said the SNP would continue to be held in regard after a Yes vote while independence would "liberate" conservative-minded Scots.

He said: "I agree with some commentators who have said this could, in the medium term, be a liberation.

"There is bound to be the evolution of a right of centre party in Scotland because so many Scots feel that way."

Professor Devine cast doubt on Labour's prospects, saying the party was "half way through a period of redemption but still has a long way to go."

He added: "The Labour Party has got to do something quite radical to improve the quality of its MSPs at Holyrood because it is not as good as it could be."