SNP supporters are the most enthusiastic backers of a referendum on a final Brexit deal, adding to pressure on Nicola Sturgeon to get behind a so-called People’s Vote.

The largest poll of Scottish voters since the EU referendum found 65 per cent of those who backed the SNP last year want a public vote on the outcome of the Brexit negotiations.

Two-thirds of those who voted SNP at the general election also want Ms Sturgeon to campaign for a public vote, something she has so far refused to do.

Most Scottish LibDem and Labour voters also want a public vote, but are less enthusiastic (62 and 56 per cent respectively), while 63 per cent of Scottish Tory voters oppose one.

Overall, 48 per cent of Scots want a public vote, 31 per cent are opposed and 22 per cent don’t know, compared to 45, 34 and 22 per cent respectively for the UK as a whole.

The YouGov poll of 2000 Scottish adults also showed Scotland is now keener about staying in the European Union than ever, with 66 per cent of decided voters backing Remain and 34 backing Leave, compared to the 62-38 split two years ago.

SNP voters are the strongest Remain supporters, backing it 83-17, suggesting a recent swing against Brexit among many Nationalists, a third of whom voted Leave.

In the UK as a whole, sentiment has also shifted in favour of Remain, but only just.

Just 12 per cent of Scots expect the UK to get a “good deal” from the Brexit negotiations, in which Theresa May is pushing her soft Brexit Chequers plan, and 68 per cent a poor one.

The poll was commissioned by the People’s Vote campaign which is holding a rally in Edinburgh this Saturday in support of a public vote on the final outcome of the Brexit talks.

The survey found a remarkable 86 per cent of Scots (95 per cent of SNP voters), regarded the process of leaving the EU so far as “a mess”.

It also found 65 per cent of Scots felt the UK government was ignoring Scotland’s concerns on Brexit, 70 per cent did not trust Westminster on Brexit, and 80 per cent, including most Leavers thought the promises of Brexiter politicians would be broken.

Most SNP, LibDem and Labour voters said Brexit would weaken the economy, cost jobs, lower living standards, hurt the NHS, raise taxes and make today’s children worse off.

Most Scottish Tory voters said Brexit would improve the same things or have no impact.

Asked if Brexit would make Scottish independence more likely, 43 per cent said yes, 6 per cent said less likely, and 35 per cent said it would make no difference.

The People’s Vote campaign said the findings would “pile pressure” on the SNP and Labour leaderships to support a vote on the Brexit outcome.

Former YouGov president Peter Kellner said: “Support for a public vote on the outcome is growing across the UK but is particularly strong in Scotland.

“There is deep pessimism about what Brexit will mean for Scotland and the next generation.

“The survey suggests the leaderships of both the SNP and the Labour Party are in the wrong place with most of their supporters.

“There may be an electoral dividend in Scotland for one of these parties if they strengthen their position. For instance, by a margin of three to one Labour supporters want Jeremy Corbyn to campaign for a public vote while Nicola Sturgeon may yet want to move faster than she has in backing such a route on Brexit.”

The First Minister has said the SNP will not be a block to a vote on the Brexit deal, and said such a vote may be “irresistible”, but has never endorsed it.

Many Nationalists fear that if the SNP backed a second EU vote it would set a precedent that would be used against them in the event of a Yes to independence.

Former SNP minister Alex Neil, who backed Brexit, said: “If we supported a second Brexit referendum, when we win Indyref2, the Unionists would demand an Indyref3 to overturn it.”

A separate poll for the Left Foot Forward website yesterday found most voters in the UK would blame Theresa May for a no-deal Brexit rather than the EU.

Scottish LibDem leader Willie Rennie warned Ms Sturgeon and Scottish Labour leader Richard Leonard were “out of step” with the country.

He said: “The benefits of remaining in the EU are irreplaceable and the people can see quite clearly that whatever deal the Conservatives patch together will not be as good as the one we have now. But even as the Conservatives bumble towards a cliff edge, Scottish Labour and the SNP are still refusing to swing into action.

"Every day that passes Nicola Sturgeon and Richard Leonard are looking more out of step with the people of Scotland. They need to end the ifs and buts and listen to the huge majority of Scots calling for a final say."

An SNP spokesperson said: “It is a democratic outrage that Scotland is being forced out of the EU against our will. People in Scotland voted overwhelmingly to remain in the EU and the SNP continues to believe this is the best option for Scotland’s future.

We will not be a block on a second EU referendum but the views of the people of Scotland must not be ignored all over again if there is to be another vote.

"The Tories now think they can do anything they want to Scotland and get away with it. Their extreme Brexit is threatening jobs, livelihoods and the interests of ordinary people, as well as the powers of the Scottish Parliament.”

Former Labour PM Gordon Brown yesterday told the Edinburgh Book Festival more than 1m Labour Leave voters across the UK had turned against Brexit.

A Scottish Labour spokesperson said: “A second referendum is not Labour policy and wasn’t in our manifesto. Labour has always insisted that Parliament has a meaningful vote on the final Brexit deal."