The UK Supreme Court was on Tuesday urged to rule on the legality of Scottish moves to hold a new referendum on independence next year without the consent of the government in London.
First Minister Nicola Sturgeon's nationalist government in Edinburgh wants a fresh vote on the question: "Should Scotland be an independent country?"
Her SNP ran in the 2021 Scottish parliamentary elections on a promise to hold a legally valid referendum after the Covid crisis subsided.
It now wants to go ahead but the UK government, which has to give approval under the Scotland Act 1998, has not given permission.
Opening the court proceedings, Lord Advocate Dorothy Bain, Scotland's top law officer, said the issue of Scottish independence was a "live and significant one in Scottish electoral politics.
"The question of whether such a poll is within the competence of the Scottish parliament... is an issue that I invite this court to finally resolve," she said.
No respect for Scottish democracy
On Monday, Sturgeon told her Scottish National Party's annual conference the hearing would not have been necessary if the UK government in Westminster respected Scottish democracy.
"But Westminster has no such respect. That means this issue was always destined to end up in court sooner or later -- better, in my view, that it is sooner," she said.
"If the court decides in the way we hope it does, on 19 October next year there will be an independence referendum."
The Supreme Court hearings will see senior lawyers wrangle over the powers of the devolved parliament in Edinburgh versus Westminster.
New UK Prime Minister Liz Truss in a television interview this month reiterated her view that the last referendum in 2014 was a once-in-a-generation event.
"I'm very clear there shouldn't be another referendum before that generation is up," she added.
UK Scottish Secretary Alister Jack told a Cabinet meeting on Tuesday that "people in Scotland want their governments to be working together on the issues that affect them, rather than focusing on another referendum", Truss's spokesman said.
Scottish voters evenly divided
Opinion polls now indicate that voters in Scotland are near evenly divided over the question of independence.
The last referendum in 2014 saw 55 percent of Scots vote "no" to breaking away.
But this came before Brexit, which most in Scotland voted against, and the parliamentary election, which saw a majority of pro-independence lawmakers elected for the first time.
The Scottish government wants to be able to create its own legal framework for another vote, arguing that the "right to self-determination is a fundamental and inalienable right".
If defeated in court, the SNP plans to make the next general election, due by January 2025 at the latest, a de facto referendum, campaigning on a single issue.
