It was supposed to be the economic equivalent of shock and awe. When George Osborne announced during a flying visit to Edinburgh, “If Scotland walks away from the UK it walks away from the pound”, the unionists hoped to strike a fatal blow to the campaign for Scottish independence before September’s referendum. It hasn’t quite worked out that way.

The Chancellor was backed by the Shadow Chancellor, Ed Balls, and the Liberal Democrat Treasury Secretary, Danny Alexander. A host of large companies including BP, Sainsbury's and Shell issued shareholder warnings about the possibility of "monetary uncertainty" damaging their business. Standard Life, the Edinburgh-based insurance giant, said it was already making plans to relocate to London, along with Scotland's biggest bank, Royal Bank of Scotland.