The judgment is a setback for the Scottish authorities's marketing campaign to interrupt away from the UK.
The highest court docket dominated that the Scottish Parliament "doesn't have the facility to legislate for a referendum on Scottish independence".
Supreme Courtroom President Robert Reed stated the 5 justices have been unanimous within the verdict.
The semi-autonomous Scottish authorities needs to carry a referendum subsequent October with the query "Ought to Scotland be an impartial nation?"
The Conservative UK authorities in London refuses to approve a vote, saying the query was settled in a 2014 referendum that noticed Scottish voters reject independence by a margin of 55 per cent to 45 per cent.
The professional-independence authorities in Edinburgh needs to revisit the choice, although, arguing that Britain's departure from the European Union — which a majority of Scottish voters opposed — has radically modified the political and financial panorama.
First Minister Nicola Sturgeon argues that she has a democratic mandate from the Scottish individuals to carry a brand new secession vote as a result of there's an independence-supporting majority within the Scottish Parliament.
Throughout Supreme Courtroom hearings final month, Dorothy Bain, the Scottish authorities's prime legislation officer, stated the vast majority of Scottish lawmakers had been elected on commitments to carry a recent independence referendum.
She additionally stated a referendum could be advisory, somewhat than legally binding — although a "sure" vote would create robust momentum for Scotland to interrupt away.
UK authorities lawyer James Eadie argued that energy to carry a referendum rests with the UK Parliament in London, as a result of "it is of crucial significance to the UK as a complete", not simply Scotland.
Polls recommend Scots are about evenly cut up on independence — and likewise that a majority of voters are not looking for a brand new referendum anytime quickly.
Independence supporters plan to rally exterior the Scottish Parliament in Edinburgh and at different websites later Wednesday.
Scotland and England have been politically united since 1707. Scotland has had its personal parliament and authorities since 1999 and makes its personal insurance policies on public well being, schooling and different issues.
The UK-wide authorities in London controls issues akin to defence and monetary coverage.
Sturgeon has stated that if her authorities loses the court docket case, she is going to make the following UK nationwide election a de-facto plebiscite on ending Scotland's three-century-old union with England. She has not given particulars of how that will work.