And so another nail is hammered into the coffin of Alex Salmond's fantasy of Scottish independence. Like him or loathe him, the Scottish National Party leader stole a march on pro-unionists with his rosy vision of Scotland retaining everything that suits it (from North Sea oil revenues to a seat at Nato) and throwing off everything that does not (namely, interference from Westminster), all accomplished smoothly by dint of one simple vote.

Thankfully, reality is now intruding. Scotland's First Minister has already been discomfited by Brussels' hints that were Scotland to split from the UK, it would have to re-apply to join the EU. But that is just the beginning. According to legal advice commissioned by the UK Government, a newly independent Scotland would need to renegotiate many thousands of international agreements, not least its membership of the UN, the International Monetary Fund and the World Trade Organisation. Normally, such advice is confidential. In this instance, the Government was right to publish. Scotland's voters must have the facts before them, not just the rhetoric from Mr Salmond.

Nicola Sturgeon, the SNP's deputy leader, has tried to lessen the blow by suggesting that, because such treaty renegotiations are not considered impossible, the lawyers' conclusions strengthen the pro-independence case. She is missing the point. Few doubt that Scotland can survive alone; and Scottish citizens must, of course, be free to choose independence. But the question – given the benefits of membership of the UK, and the increasingly evident upheavals and uncertainties of leaving – is why they would want to.

Nor does the economic assessment commissioned by the Scottish Government provide a persuasive response. The panel stresses that a go-it-alone Scotland would be best retaining sterling, sticking with the Bank of England and establishing a high-level committee to oversee monetary union. Again, such things are not impossible. Indeed, the chairman of the Fiscal Commission Working Group explicitly states that "Scotland has the clear potential to be a successful independent nation". But his conclusions cannot but raise a query as to the point of independence. It is a question to which Mr Salmond's answers are ever less convincing.