'Now is not the time' except, apparently, when now is the time. The reasons for engineering a general election are many and obvious. The current government is tolerated, not welcomed. Theresa May needs a mandate of her own. A thumping Tory majority - the only conceivable outcome of any dash to the country - will not hugely strengthen her position with Britain’s erstwhile european friends and partners, but it will secure her position on the domestic front.

For Labour, too, this is an opportunity to lance a boil: it will, or should at any rate, end the Jeremy Corbyn era. For their part, the Liberal Democrats should welcome the opportunity to make their pro-EU - or, rather, anti-Brexit - pitch to the electorate. It is not difficult to see how they could gain some seats from doing so, rallying Remoaners (sic) to congregate in the last ditch of a lost cause.

One thing is already clear, however: if there is an election, the Scottish portion of it will be very different from the election that will be held in England and Wales. It will be, in effect, a single-issue election to answer just one question: should there be a second independence referendum?

The game of defining 'victory' has already begun. Unionists will do their best to make the argument that unless the SNP repeat their stunning 2015 success - when they took almost 50 percent of the vote and won 56 of Scotland’s 59 constituencies - they will in some mysterious sense have 'lost' the election. Their mandate for a second referendum will be diminished. Scotland will have said No. (Again.)

Well, good luck with that. The 2015 general election was a different beast living in a different era. It was a wave election that realigned Scottish politics, cementing the SNP’s position as the dominant force north of the border. It was an election about political identity and sympathy, certainly, but it was not a battle pitched on the idea of a second independence referendum. That was not then on the table.

It is now and for all that nationalist agitators have never given up on the idea of a second plebiscite, that referendum is on the table because Brexit has put it there. This is what Theresa May warned of herself when she counselled voters to vote to Remain members of the European Union. Now her own prophecy returns to bite her.

In the old days, the SNP argued that winning a majority of Scotland’s Westminster seats would be a sufficient mandate to open independence negotiations. Those rules no longer apply now that the referendum has set a precedent. Indeed, parking independence was a key part of the SNP’s long rise to power. It allowed voters to endorse the party without having to support independence. But the longer a voter supports the SNP, the more probable it is that eventually they will come round to supporting independence too. Voting SNP changes voters.

Still, independence cannot now be delivered without a referendum. Anything else offends the people’s inchoate sense of how the game should be played. But since the UK government has hitherto suggested the SNP lack a mandate for a second referendum - having lost seats at last year’s Holyrood election - it seems modestly idiosyncratic to hand them an opportunity to renew and reaffirm that mandate in June.

Because, make no mistake, that is what the Prime Minister has done this morning. Talk about how the SNP need to win 50 percent or more of the Scottish vote is just that: talk. That’s not how the game is played. If it were then any government failing to win 50 percent of the popular vote would have its mandate questioned. But that it not how we organise matters in what we can still, at least for now, call this country.

If the SNP win a majority of Scottish seats at a general election that is in effect a vote to decide whether there could or should be another independence referendum then that, by god, is a mandate. The will of the Scottish people, for better or worse, will have been made clear. If you have the votes, you have the votes.

That does not, of course, require the Prime Minister to accept or agree to schedule a second independence referendum but, should the election pan out like this, she has immeasurably strengthened the moral case the SNP will make to argue for a second referendum. She won’t be able to hide behind talk of 'mandates' any longer.

The case for independence itself remains unproven, of course, but that is a matter of secondary importance right now. Right now the argument is over whether or not there is a case for a second referendum. Until now, Unionists had on the whole the better of that argument, not least because a referendum inspired by Brexit could not sensibly take place until such time as the impact of Brexit is felt and understood.

Theresa May burnt that argument this morning. She did so as a Conservative, not as a Unionist. That is her choice, her prerogative. But it remains something she did not have to do.

2015 was, in many ways, a freak election for the SNP. Everything that could go right did go right. That may not happen again. They could indeed lose seats. In fact they probably will. But it is hard to see how they can fail to win a majority of Scottish constituencies and hard again to see how winning an election does not give them some kind of a mandate for a second referendum. If an election is not the expression of the will of the people then what is?

Mrs May cannot win a mandate for herself while then denying a mandate to the party that wins the Scottish portion of this election.

'Now is not the time' never answered the national question anyway, not least since it allowed that at some point in the future now could be the time. But that was then and this is now and so now might well be the time rather sooner than anyone, including Mrs May, had thought. That's on her.