With the possibility of a second referendum on Scottish independence already a major talking point of the 2019 general election campaign, the survey of 1,001 adults from across Great Britain found many are increasingly pessimistic when asked about present constitutional arrangement.
When asked if the UK would exist in its current form in 10 years, 50 per cent of respondents said it would not - a seven per cent increase from when pollsters Ipsos Mori asked the same question in June 2014.
Opinion was more evenly split when respondents were asked if the UK would exist in five years - with 44 per cent saying it would not and 42 per cent saying it would not.
Confidence in the Union's future was highest among Conservative voters, with 42 per cent believing it would exist in its current form in 10 years - compared to just 23 per cent of Labour voters.
Emily Gray, managing director of Ipos Mori Scotland, said: "While no one would expect public confidence in the Union’s future to be higher now than it was five years ago, what’s striking is just how much it’s dropped.
"These findings show that the British public are now much more divided in their expectations of the Union’s future than they were in 2014, when the Union’s future was under intense debate with Scotland just three months away from an independence referendum.
"With independence a key faultline in Scotland’s election debate, the findings will be concerning for those who want Scotland to remain in the Union, while those campaigning for an independent Scotland will hope that this is a continuing trend."
Tommy Sheppard, the SNP’s candidate for the Edinburgh East constituency, said: “This poll shows that voters up and down the UK recognise that this is no union of equals as Westminster parties would have you believe - this was laid bare for all to see throughout the Brexit process.
“Time and time again Scotland has been ignored and side-lined - it is no wonder that polls are showing decreasing confidence in the union and rising support for an independent Scotland.
“Everyone knows an independence referendum is coming – and on December 12 a vote for the SNP is a vote to put Scotland’s future in Scotland’s hands and escape this broken Brexit Britain.”
Pamela Nash, chief executive of Scotland in Union, said: “It’s clear that breaking up the UK would be infinitely more chaotic than leaving the EU, as 60 per cent of Scotland’s trade is with the rest of the UK, and our economy and institutions have been intertwined for centuries.
“With the SNP proposing a new currency and a hard border at Berwick and Gretna, hundreds of thousands of former Yes voters now want to remain in the UK.
“The best future for Scotland is to remain in the UK, saving the pound, avoiding a hard border with England, and maintaining the bonds between friends, families and neighbours across the UK.”