This year is the 300th anniversary of the political Union of Scotland with England. If opinion polls are right, the separatist Scottish National party will be the largest grouping in the new Scottish assembly in May.

The economic argument was set out in the Financial Times on December 12 in parallel contributions from Alex Salmond, leader of the SNP, and Wendy Alexander, the most articulate of Labour’s Scottish economic spokesmen. Scotland consumes a little over 10 per cent more than it produces and a separate state would face deficits of this order in public finances and on trade. About half of this figure is Scotland’s pro rata share of current UK imbalances.