Theresa May has been accused of blocking a second independence referendum because she knows she can’t win.
The prime minister was also warned last night that her actions would only increase support for the nationalist cause.
But unionist party leaders backed her decision, insisting now was not the time for another “divisive” poll.
Business for Scotland chief executive Gordon MacIntyre-Kemp said David Cameron had agreed to both the 2014 and EU referendums because he thought he could win.
But he added: “Theresa May has decided to attempt to block a Scottish referendum because she knows she can’t win.
“The planned hard Brexit absolutely and utterly destroys the economic case for Scotland remaining in the UK.”
Aberdeen South MP Callum McCaig also hit out at the prime minister.
“Just imagine Brussels had told the UK that they are not allowed to have a referendum,” he said. “That’s the difference between Scotland’s ‘two unions’.”
Ross Greer, the Scottish Greens’ external affairs spokesman, said Mrs May’s comments underlined the Tories’ “contemptuous attitude” toward Scotland.
He added: “If a Tory Westminster Government that Scotland did not elect seriously think they can block our right to choose – and that they can veto a decision of our elected parliament – they will only increase support for independence.”
But Scottish Liberal Democrat Leader Willie Rennie agreed now was “not the right time”.
He added: “There is not public demand for one and there is not a proper mandate for one.”
Scottish Labour Leader Kezia Dugdale said her party would vote against Ms Sturgeon’s plan and insisted there “absolutely should not be another independence referendum until after Brexit”.
The matter is due to come before the Scottish Parliament on Wednesday when a majority of MSPs are expected to back the first minister’s call for another poll.
Aberdeen-born Ms Dugdale said the SNP Government needed to focus on the “day job”, adding: “Scottish Labour believes that together we’re stronger, and the Labour party I lead will never support leaving the UK.
But she added: “If after Brexit we have that clarity and the people of Scotland want a referendum on leaving the UK then it isn’t the job of the UK Government to stand in the way of that.”
