Who will blink first in the independence stalemate?

Boris Johnson has denied Nicola Sturgeon's request for indyref2 - but the battle doesn't end there.

When Nicola Sturgeon read the Prime Minister’s response to her request for the devolution of powers to hold a second independence referendum, she probably thought, ‘it took him weeks to write this?’.

The letter is relatively short and to the point, steering clear of any substantive arguments about Brexit, political mandates and the dangers of a protracted constitutional stand-off, which this letter confirms is now official.

The temperature just rose a notch this morning as the relations between the two governments hits an all-time low. January 31 will do nothing to usher any entente cordiale.

Last weekend’s march for independence demonstrated that this issue will not go away. Having asked for the power to hold a new plebiscite and having been rebuffed, the ball is now in the First Minister’s court. The debate now shifts to plan B, if indeed there is one.

What the Scottish Government now does is anyone’s guess. For his part, Mr Johnson has decided that it’s a case of not now and not in the lifetime of this parliament – a line echoed by the Scottish Secretary Alistair Jack at the weekend.

The high-wire act here is being played by the Prime Minister and if he wobbles as a result of miscalculation, then the end of the Union could be his enduring legacy, not Brexit.

The Tories are hoping that the SNP or, more accurately, Holyrood’s pro-independence majority is lost next year at the Scottish elections.

Gamble and risk, two words I would readily associate with the Prime Minister. Those character traits led him to seeking a UK election last December, a gamble which endowed him with a substantial parliamentary majority.

But this is arguably a more complex issue to deal with than Brexit. Unless support for the SNP starts to drop materially he could be the architect of the downfall of the Union that means so much to him.

What will be interesting is to see whether the broader independence movement calls for a strategy rooted in living a little dangerously. Nicola Sturgeon talks bullish but is a politician for whom caution is a watchword as well as a tactic

She asked, he rebuffed and they now face one another in a spirit of mutual antagonism. This is not about who blinks first but what new event is going to change the current dynamic of political stalemate.