This strategy could only deliver the required result on two conditions: first that the Celts remain satisfied with this partial autonomy, so as happily to remain within the United Kingdom; and secondly that the English be rigorously prevented from acquiring a parliament of their own. Inevitably, however, the process of devolution, once set in motion, has gathered a momentum of its own, and we face the real possibility of a break-up of the United Kingdom. A party whose leaders are mostly Scots, who rely on the Scottish vote to govern the English, and who have devoted the last nine years to the demolition of institutions towards which many English people feel a real, if sometimes irrational, affection, is clearly inviting an upsurge of English nationalism.

The attempt by the deputy prime minister John Prescott to follow the notorious European Union map of our continent, and to divide England into artificial regions, four of which would have their own elected assembly, has backfired (notably in the rejection by voters in November 2004 of plans for such a body in England's northeast); in any case the creation of regional assemblies would merely amplify the demands of the English for a government of their own, within a loosely defined union of the kind exemplified after 1945 by the British Commonwealth.

Well, why not? The British government made a great mistake in holding on to Ireland long after the Irish people had made it clear that they wanted to govern themselves - a mistake that jeopardised the kingdom during the first world war, and led to Irish neutrality, and the resulting loss of a vital ally, during the second. Of course, the Labour Party is determined to prevent the birth of an English parliament, knowing that such a parliament will be dominated by the Conservatives for the foreseeable future - a disastrous outcome for Labour, given the fact that England remains the economic and cultural heart of the United Kingdom. The attempt by Gordon Brown (the Scot who is Britain's chancellor, and Tony Blair's probable successor as prime minister) to forge a British identity can be seen as a characteristically astute response to this emerging danger. Only if the English can be prevented from identifying themselves as such, will the pressure for English autonomy be diverted.

Unfortunately, however, the English are less likely to identify themselves with the United Kingdom, now that the Celtic parts of it are enjoying the fruits of self-government; and in any case, Britishness, insofar as it has ever existed, was always an extension of an identity forged in England and responsive to the language, religion, culture and imperial politics of the English crown.

As to the question whether the break-up of the kingdom can be peacefully managed, it seems to me that this is the easiest to answer. Neal Ascherson points out in the London Review of Books that there is a clear precedent before us in the break-up of Czechoslovakia, where a country - admittedly of recent creation - divided peacefully along the ancient faultline between Austria and Hungary, while maintaining good relations, and privileged social, economic and legal ties (see "Diary", 5 April 2007 [subscription only]).

True, the book Ascherson draws on to make his case - Abby Innes's Czechoslovakia: The Short Goodbye - argues that disunion was the product of political orchestration rather than the natural restoration of historic boundaries. But a workable outcome has survived a precipitous process. The problems that existed in the Czech and Slovak case, and which worry observers of the United Kingdom (such as the unequal distribution of populations, natural resources and skills), have been peacefully accommodated. More important, since the divide, the more belligerent and chauvinistic form of Slovak nationalism, associated with Vladimír Meciar, has become largely irrelevant, to the great relief of the Hungarian and Roma minorities. The first result of the split between the Czech lands and Slovakia was a much needed lowering of the political temperature.

Influence

The third question is surely the most serious: does not every division weaken the ability of a country to hold its own in the world, whether in the commercial, the diplomatic or the military sphere? How would England, as sole heir to the vestigial obligations of empire, succeed in meeting those obligations? What would happen to the armed forces, for example, when the Scottish regiments and Scottish bases and naval facilities are controlled from Edinburgh? Such questions are not high on the Labour Party agenda; but they will be high on the agenda of a future Tory government, seated in a purely English parliament. And they might involve a complete rethinking of England's position, not only vis-à-vis Nato, but also as a member of the European Union, and a contributor to its global policies.

Indeed, the EU is certain to oppose the break-up of the union. Instead of two low-tax liberal economies - the UK and Ireland - it would have to face four, each resisting the attempts by France and Germany to export the cost of their state-controlled economies by unifying taxation across the continent. The French would certainly wish to exploit ancient alliances and antagonisms, in pressing for a dirigiste economy in Scotland, and a high-tax regime across Great Britain. And would our vestigial nation-states be able to stand up to the pressure?

Even so, we should not assume either that England would lose its pre-eminent international role, or that such weakening as might occur would necessarily be bad for us. Maybe less time spent in policing distant waters would give us more time and energy to police our own borders. Maybe a renewed sense of England as our much diminished home would stir a new desire to defend it and to enhance its negotiating powers. Maybe England will emerge from the final fragment of its former empire with a new sense of why it matters to survive. If that were the result of separation, what English patriot could be opposed to it?