Michael Russell

Michael Russell made the comments at the SNP conference in Aberdeen, despite the fact that First Minister Nicola Sturgeon has previously said that fault would lie with Westminster.

The court is hearing arguments this week on whether a second independence referendum would be within the power of the Scottish Parliament.

Ms Sturgeon said that if the court finds that it cannot hold one, she will contest the next general election as a “de facto referendum” on the question of independence.

Mr Russell, a former Constitution Secretary and head of the party’s Independence Unit, said yesterday: “There is no great in Great Britain. And our choice is stark and clear.

“Decline with the UK, or prosper as a small independent normal country within the EU. Now we know when we’re going to make that choice. If the Supreme Court rules in our favour, then it will be on the 19th of October next year.

“And if the Supreme Court fails the people of Scotland, then we will rise to that challenge too, and put our case at the next general election whenever that is.”

In June Ms Sturgeon said: “It is possible that the Supreme Court will decide that the Scottish Parliament does not have the power to legislate even for a consultative referendum.

“To be clear: if that happens, it will be the fault of the Westminster legislation, not of the court.”

A five-justice bench will hear whether a referendum would “relate to” the reserved issue of the union tomorrow and Wednesday.