IT is clear that the issue of EU membership is throwing up all kinds of problems for Scottish Nationalists.

The failure to think through the implications of "Scotland in Europe" over the past 40 years is just the start: not clarifying the legal question of Scotland's continuing membership and not thinking through the matter of currency under independence constitute negligence by First Minister Alex Salmond. But rolling over the horizon is an even more formidable problem: a UK referendum on membership of the EU.

Most Unionists have come to the view that the UK would do better to loosen ties with the EU. The SNP quite rightly asks of us how can it be logical to withdraw from one union, but defend another to the death. The answer is simple: the UK has a unity of culture, philosophy and political economy which the rest of the EU does not share. With standard English universally spoken, and with electronic media compressing time, distance and experience, locality as a unique place of nurture for varied cultural perceptions has disappeared here: Scottish and English cultures have faded into Britishness.

Following in the philosophical footsteps of that titan of the Scottish Enlightenment, David Hume, the British tradition is empiricism. We give up on schemes if they do not work; we do not break people and societies in the cause of a grand theory, as the past and current leaders of the continental powers have done, and are doing today with the single currency and the pursuit of political union. Our own single currency, combined with a fiscal and a banking union, has worked for 300 years, producing a uniquely homogeneous space in terms of income, output, trade, employment, economic opportunity, personal mobility and, compared with other countries, racial integration.

A referendum on UK membership of the EU holds no fears for Unionists. The Prime Minister wants to renegotiate Britain's terms of membership and stay in. However, Georg Boomgaarden, the German ambassador to London, and Gunther Krichbaum, the Chairman of the Bundestag European Affairs Committee, both reflecting Mrs Merkel's position, have warned that there will be no choice between renegotiation and exit ("Cameron is warned over EU 'blackmail'", The Herald, January 11). Such is the mood of the British public, and notwithstanding the views of the Americans, Lord Heseltine and a few leading figures in the City and industry, it is all but inevitable that we shall be leaving the EU.

As, no doubt, Whitehall has already worked out, an EU referendum will do for the SNP, even though it will occur after the Scottish independence referendum in 2014 and after the next Westminster election in 2015. Whether or not it votes for independence, Scotland will still be part of the UK and EU after these dates. However, the prospect of the uncertainty created by an impending EU referendum will almost certainly produce a No vote in Scotland in 2014. In the highly unlikely possibility of Scotland voting Yes in 2014, an EU referendum, whether the result be "in" or "out", would so hugely complicate the ensuing independence negotiations that a second Scottish referendum on the terms would be unavoidable. That too would produce a No vote.

Richard Mowbray,

14 Ancaster Drive, Glasgow.