PM knows that the Tories are toxic for Scots
In just a week's time, Scotland will go to the polls. It looks like being a close-run thing – so close, in fact, that David Cameron, the Prime Minister, is getting quite emotional.
"I love my country more than I love my party," he said, telling the Scots that he would be "heartbroken" if they left the UK.
It is hard to tell if the appeal will have the intended effect, or if Scottish voters will rub their hands at the prospect of leaving a Tory Prime Minister heartbroken.
His party's popularity is at an all-time low, and its Scottish vote has fallen steeply for more than six decades.
Back in 1950, the Conservatives got half of the vote. This year, they got 17.2% of it in the European election. That was probably boosted by a low turnout – they scored 13.2% in the 2011 Scottish parliamentary elections and have just one Scottish MP at Westminster.
The Tories are a diminished force in Scotland compared to England and Wales. In fact, Alex Salmond, the SNP leader and Scottish First Minister, has used the prospect of continuing to be ruled by a Tory government in Westminster as one of the main planks of his campaign for voting for independence. Yesterday, even Mr Cameron warned voters not to be tempted to vote for the irrevocable step of independence just to give the "effing Tories" a kick, as they might in a general election.
Labour, traditionally the strongest party in Scotland, was overtaken in the SNP landslide of 2011, and the prospects of winning some of these lost Labour voters back may be damaged by their association with the Tories in the No Campaign – at least, that is what the SNP hopes.
No campaigners tell me that the key demographic on which the poll may hinge is Labour voters of Irish descent in areas such as Glasgow, Ayrshire, Renfrewshire and West and East Dunbartonshire. It is that close.
Caution – Cameron's line of not taking an irrevocable step whose effects would last for a century or more – is the No campaign's main hope to win back these marginal voters in the final days.
That appeal will be accompanied by a timetable for the devolution of taxation and welfare powers to Scotland if they vote No.
This "devo max" package, it will be argued, will provide something like home rule for Scotland – without the risks of going it alone.