BREXIT is behind a definite shift in support for Scottish independence, with Remain voters the key group swinging behind Yes, the country’s leading pollster has said.

Professor Sir John Curtice said a poll this week showing a majority of decided Scots voters now back independence reflected a wider pattern.

Conducted by Tory peer Lord Ashcroft after Boris Johnson became Prime Minister, it found 52-48 support for Yes, the first survey since March 2017 with such a result

Speaking to the LBC presenter Iain Dale at the Edinburgh Fringe, Prof curtice said it was “part of a trend”.

He said: “Prior to that poll, we had four other polls this year, and they on average had Yes at 48 [%]. Whereas all the polls in the second half of last year on average had Yes at 45.

“So there was already evidence of a small trend, but it doesn’t need to be a big trend to shift it. All of the movement last year has occurred among Remain voters in Scotland. Leave voters haven’t shifted.

“One of the ironies of the 2014 referendum is that we had this enormous row about whether an independent Scotland would or would not be able to maintain continuous membership of the European Union.

“It was completely irrelevant. There was no relationship at all between people’s attitudes towards the EU and whether they voted Yes or No. Now there is. The two things have got intertwined.”

“Does that mean however that the SNP can call a referendum tomorrow with confidence? No. Basically, they would need many more polls showing bigger leads.”

He also said that it was “now too late for us to leave the European Union on 31st October with any kind of deal” because there not enough time to get the required legislation through the Commons and Lords, even if MPs finally agreed on a deal.

However he said that did not necessarily mean a no-deal Brexit, as if a deal was almost done, Mr Johnson might request a short extension to complete it, or the PM might be brought down in a no-confidence vote or MPs might revoke Article 50.

He also said one of the biggest changes of recent years was an alignment between voting patterns at Westminster and Holyrood elections.

Previously, Scottish voters had been willing to back the SNP for Holyrood, but markedly more reluctant to do so at Westminster.

But that changed at the 2015 general election, and the SNP now has around 40% support in both.