Nicola Sturgeon’s claim that she will not contemplate breaching the rule of law by holding an independence referendum was pretty blatant trolling of Boris Johnson, given the multiple allegations he faces of being less than scrupulous in following domestic and international law.

But Sturgeon also put Johnson and the Tory party in a tight corner by asking the Lord Advocate to petition the Supreme Court in London to determine the legality of a referendum.

If the Supreme Court rules her way, then there will be the mother of all constitutional crises if Boris Johnson continues to reject the lawfulness of any vote by the Scottish parliament to hold a poll on 19 October 2023.

And if the Supreme Court rules against her – and there is a reasonable chance it will – then she says she will fight the next general on one issue alone, that Scotland should be independent. The general election would be her referendum, she says.

Either way, for the Conservative and Unionist party – to give the Tories their full name – Sturgeon has turned the Scotland question into the Boris Johnson question. The point is that Boris Johnson is even less popular in Scotland – where a staggering 83 per cent of adults said they were dissatisfied with him in a recent Ipsos poll – than he is in England.

So as MPs in the Tory party – whose very identity is for the union – continue to agonise about whether to replace Johnson as their leader and PM, they now need to decide not only whether he will lose them their own seats, but also the whole of Scotland to boot.