Clearly it’s a very high-stakes situation for both Alex Salmond and David Cameron, but there’s a feeling in England that if Scotland was to become independent some people – perhaps some Tory back-benchers – would say “Halleluiah”.
Some Tory back-benchers might take the view that without Scotland there would have been a Tory government for the UK at almost every general election after the Second World War.
David Cameron would not want to be the Prime Minister who lost Scotland for the UK, just as Winston Churchill said he did not want to be the prime minister who lost India.
But while Mr Cameron doesn’t want to lose the Union between Scotland and the UK, the stakes are much higher for Alex Salmond. From his point of view, if a referendum were defeated, he could not keep holding one after the other.
Clearly one problem is that the SNP has been very disciplined, but how long would that last if it were to be defeated in a referendum?
Mr Salmond resigned as party leader once before, and if he lost an independence referendum his heart would no longer be in it, as independence has been his whole political life and is what he’s campaigned on for 30 years.
Mr Cameron, on the other hand, would still be Prime Minister of England if Scottish independence was to be approved in a referendum. In that way, he’d still have his role at the United Nations and in Europe.
This suggests there is much more at stake for Alex Salmond than David Cameron, who, in his worst-case scenario, would lose the Union with Scotland, but then be left with an inbuilt Tory majority for his party in the rest of the UK.
We see very clearly that Mr Salmond wants to have a referendum later, as that’s when he thinks he has the best chance of winning a Yes vote.
At the same time, Mr Cameron wants to hold a referendum earlier for exactly the same reason – that’s when he thinks he is more likely to win.
lTrevor Salmon is professor of politics at the University of Aberdeen.