Sturgeon is finally arrested and the SNP's political crisis deepens.

They thought Operation Branchform was all over, it isn't now.

I was writing a Substack on Boris Johnson’s resignation this afternoon when the news broke that Nicola Sturgeon had been arrested “as a suspect” by Police Scotland. It’s hard to keep up. Politics north and south of the border seems to be going slightly mad in the heat.

We had of course been expecting Nicola Sturgeon’s arrest - I’d forecast it several times. The SNP was braced for it six weeks ago. But that didn’t make the sight of the former First Minister of Scotland being taken into police custody any less extraordinary and, to many SNP observers, any more justified.  In fact, the delay made today’s events even more shocking than might have been the case back in April after her husband, the party chief executive, Peter Murrell, was collared by the polis and released without charge - as Ms Sturgeon has been.

The lack of news from the police investigation had led many in the SNP to start speculating, as the former SNP spin doctor, Murray Foote put it, that Operation Branchform had turned into a “wild goose chase”. Perhaps the evidence collected by police had not stacked up, mused party workers. Maybe this was all heading for the long grass. Insiders confidently forecast that no charges would emerge from the Crown Office and Procurator Fiscal Service. Knives were being sharpened for the chief constable of Police Scotland, Sir Iain Livingstone, who is retiring later this year. This was, muttered SNP insiders, all about politics.