The Scottish government cannot force a second referendum on independence without Westminster's consent, the UK's highest court has ruled.
Scotland's First Minister Nicola Sturgeon had hoped to hold another poll in October 2023 on the question of whether the country should break away from the UK.
The Supreme Court was asked by Scotland’s top legal adviser to assess whether the Scottish Parliament had the power to legislate unilaterally for a consultative referendum.
In its ruling, released on Wednesday, Supreme Court president Lord Reed said: “The Scottish parliament does not have the power to legislate for a referendum on Scottish independence.”
The judges said a vote would need to be approved by the UK government, as it was when Scotland held a previous referendum in 2014.
The ruling means the Scottish government's top law officer, the Lord Advocate, will not be able to clear the bill for passage through the Scottish parliament.
The power to call a referendum was “reserved” to the UK parliament, and therefore “the Scottish parliament does not have the power to legislate for a referendum on Scottish independence”, Lord Reed said delivering the unanimous ruling.
Ms Sturgeon on Wednesday said she was “disappointed” by the decision.
“A law that doesn't allow Scotland to choose our own future without (UK parliament) consent exposes as myth any notion of the UK as a voluntary partnership,” the Scottish National Party leader tweeted.
“Today’s ruling blocks one route to Scotland’s voice being heard on independence — but in a democracy our voice cannot and will not be silenced.”
Shadow Scottish secretary Ian Murray said the court's decision should be respected — and insisted Labour could offer the change needed by the people of Scotland.
“The UK Supreme Court has made their decision and we should respect that and thank them for their work,” he said.
“The people of Scotland do want and need change regardless of their views on the constitution.
“Change is coming with a UK Labour government at the next election.”
The Scottish public rejected the prospect of independence in 2014 by a margin of 55 per cent to 45 per cent.
The pro-independence government in Edinburgh wants to revisit the decision, arguing that Britain’s departure from the EU ― which a majority of Scottish voters opposed ― has radically changed the political and economic landscape.
The semi-autonomous Scottish government wanted to hold a referendum next October with the question “Should Scotland be an independent country?”
However, the UK government has refused to grant permission to hold a second vote.
Polls suggest Scots are about evenly split on independence — and a majority of voters do not want a new referendum any time soon.
Independence supporters are expected to rally outside the Scottish parliament in Edinburgh and at other sites after the verdict.
Scotland and England have been politically united since 1707.
Scotland has had its own parliament and government since 1999 and makes its own policies on public health, education and other matters. The UK-wide government in London controls matters such as defence and fiscal policy.
Ms Sturgeon says that if her government loses the court case, she will make the next UK national election a de-facto plebiscite on ending Scotland’s three-century union with England. She has not given details of how that would work.