The surprise news story today (on the front page of the FT with the First Minister doing his best Winston Churchill impression) is that Alex Salmond believes that the UK Government should still be liable for the full £187bn that is propping up RBS even if Scotland were to win independence. In what is surely a tactical move to paint the UK as having mismanaged the economy over the recent past, Salmond’s argument goes that given the “misregulation” took place at the London Treasury, then the London Treasury should carry the can. It’s a decent try, but I can’t say that I am altogether convinced.

The pre-emptive attempt to pin RBS’ woes on London is surely an admission from Salmond that he sees this issue as a millstone, a giant crack in his argument, and he will struggle to convince voters that it’s not Scotland’s problem to deal with.

For a start, the crux of RBS’ problems, the acquisition of ABN Amro for a vastly overinflated cash price, had the blessing of the First Minister, as this link shows. I don’t see how any would-be leader of a country can cherry pick which problems they will take responsibility for and which problems they won’t, particularly when they themselves went into the troubled period with both eyes open and having been an economist at the bank in question.

Another problem is the risk of pushing away one of Scotland’s economic jewels. RBS is constantly urged to move its Headquarters down to London, a move that would be a body blow to employment in the financial sector in Scotland’s Capital. The bank has always maintained that Scotland is part of its fabric, part of its name, and will not move down south. However, if independence takes place and one Government doesn’t want to help it through a tough time while another Government does, where will the bank’s loyalty, and HQ, prove to be then?

Perhaps that is what Salmond is after. HBOS is now part of Lloyds Banking Group, reduced to nothing more than a brand and RBS is deeply troubled. Maybe Salmond is trying to create a space for a new bank to be formed that will be synonymous with a new Scotland. It’s not the worst idea in the world but it is hugely risky. To lose one bank is unfortunate but to lose two would be seen as careless.

Surely the fairest way to apportion out the expense of bailing out of RBS is to work out what percentage of income is realised in Scotland and what percentage is realised in rUK and split the £187bn by this ratio, broadly similar to how Corporation Tax would be applied. A bitter pill for Scotland to swallow but no more bitter than what we are currently having to contend with, and if these oil revenues are as lucrative as suggested then we should be able to help RBS back onto its feet easily enough. Isn’t that the independent, self-standing Scotland that the SNP aspires to?

Of course, Salmond rarely puts a foot wrong and perhaps there is an overriding incentive for the SNP to try winning this argument. A recent poll showed that 65% of Scots would vote for independence if it made them £500 richer as a result. Well, 10% of £187bn is £18.7bn which, spread across Scotland’s 5million people, is £3,740 each. More than enough money to get Scots out voting Yes.

So with a flaky kind of logic, very flaky, that’s potentially the ball game. However, crucially, it also undermines the other Nationalist argument that an independent Scotland could carry RBS’ weight so perhaps this particular ante should not have been upped in the first place.