Colin Mackay says Nicola Sturgeon's independence plan could be the biggest political move she has made

This could prove the biggest political move Nicola Sturgeon has made as First Minister. A huge gamble for a leader not known for taking risks.

It was always expected to end up in the Supreme Court, so what the First Minister is doing today is pre-empting that – instead of legislating for a referendum then seeing if it is legal, the First Minister wants to test the legality of her referendum plans first.

If the Supreme Court rules it is legal then the opposition will have no choice but to take full part in a campaign. However, if the judges say it is not legal then the First Minister wants to turn the next General Election into a vote on independence.

Before that, the Supreme Court has to accept the Lord Advocate’s request for a ruling. It seems unlikely the Lord Advocate would agree to make that request if she didn’t think there was a good chance they would take it seriously. Dorothy Bain QC will represent the Scottish Government in that case and ministers are hoping for a decision by the end of this year. It will also force the UK Government and supporters of the UK to take part in the process from the outset. If the Supreme Court were to rule that the Scottish Parliament does have the power to hold a referendum, it would also be hard to boycott.

Labour deputy leader Jackie Baillie raised an interesting point at the end of the First Minister’s statement – does all this mean if the Lord Advocate is not giving the go ahead to the Government’s referendum plans, does she not think they are legal? Opposition MSPs are now pressing the Lord Advocate to make a statement to Parliament.

All of this goes much further than was expected today. It is now clear why the First Minister has been so secretive about her plans, given that they involve serving legal papers on the UK Government, but it is still all about process, and crying “process” is a lot less exciting than painting your face blue and crying “freedom”.

But then this is less about Braveheart and more about bold thinking.