Kirsty Hughes, director of the Scottish Centre on European Relations (SCER), said the UK was heading for a “damaging” hard Brexit because Remain voters had been left with little strong representation.
The think tank has published a new report bringing together analysis of the forthcoming challenges as the process of exiting the EU unfolds.
Writing in the report, Ms Hughes said: “As the process unfolds, the UK - and particularly England - has remained deeply divided over the question of proceeding with Brexit.
“Support for ‘remain’ has moved a little ahead in the polls over the last several months but not strongly enough for many passive and fearful politicians to come out and argue to halt Brexit or to hold a further EU referendum.”
She highlighted that while the Liberal Democrats and English and Welsh Greens support a referendum on the final deal, First Minister Nicola Sturgeon has not gone so far, despite declaring it could become irresistible.
“Labour’s acceptance of Brexit has led to weak opposition to the slow, shambolic and damaging Brexit process, with Jeremy Corbyn mostly preferring to lead on domestic issues at Prime Minister’s questions each week,” she added.
“Labour has now come out in support of staying in a customs union with the EU, but while it doesn’t support staying in the EU’s single market, it is not in a strong position to challenge Theresa May and her government over the economic damage a free trade deal will do.
“Consequently, the 48 per cent who voted ‘remain’ (or the 52 per cent who now support ‘remain’ in several polls) have little political voice or representation as the UK heads towards a major and damaging political, constitutional, economic and institutional upheaval that has little precedent.
“This is true even in the two parts of the UK that voted ‘remain’ - Scotland and Northern Ireland. “
The report pulls together analysis from 15 experts and commentators from Scotland, Northern Ireland and the EU, who raise a range of issues about the Brexit process, including the prospect of a “cliff-edge” exit, concerns over citizens’ human rights, the problem of the Irish border and the challenges for devolution.
Ms Hughes said: “The path from here to an autumn withdrawal agreement is highly uncertain.
“Our new report makes clear the UK is on a path to a damaging, hard Brexit.
“And without a deal on the Irish border, the divorce deal could fall apart - and the transition deal with it - a cliff edge still looms.
“As trade talks start, unprecedented in putting new trade barriers in place, the UK could still change its mind and call a further EU referendum - Labour and the SNP for now are refusing to support this.
“UK politics is failing as it sticks to a passive ‘wait and see’ mode of opposition. And the time to halt Brexit, or even push it to a ‘softer’ Brexit, is running out.”