Leading article: The English question left over from devolution

It is not difficult to see why the Conservative Party has suddenly become interested in answering the much-debated "West Lothian question". The confirmation from the Tories this weekend that they would ban Members of Parliament from Scottish constituencies voting on legislation that applies only to England is an obvious strategic manoeuvre from David Cameron. As with the Tory leader's recent announcement on the Human Rights Act, it owes more to political opportunism than principle.

Foremost in Mr Cameron's mind is the goal of making life difficult for Gordon Brown. The Tory leader believes there is political capital to be made out of emphasising the "Scottishness" of the man widely expected to become the next Prime Minister. One suspects the Chancellor agrees, given his recent, faintly ludicrous, pronouncements on football. So what better way to do this than attempting to limit Mr Brown's voting rights?

This is a risky strategy. Firstly, it is likely to open up cracks and tensions that already exist in the 300-year-old union on both sides of the border - an odd stance for a party with unionism woven through its very fibre. Secondly, Mr Cameron is sending out a clear signal that he has written off hopes of winning back Tory seats north of the border; a remarkably defeatist stance. Thirdly, there are the implications: if he is arguing that MPs should legislate only on matters that directly affect their constituents, where should this process stop?

Yet for all this, the Conservatives have undoubtedly fired up a genuine issue worthy of serious debate. The British constitution, if examined rationally, is a deplorable mess, one that has worsened under the Blair administration. The hesitant devolution unfurled with the establishment of the Scottish Parliament and the Welsh Assembly has created a legislative anomaly. Why should contentious Government legislation be saved by the votes of Scottish Labour MPs, whose own constituents are unaffected by these new laws? This is thrown into sharper focus by the fact that, due to demographic shifts and geographic reality, it takes fewer votes to elect an MP in Scotland than in England.

It would be nice if we could assume the West Lothian question is like one of those fiendish puzzles of logic with a simple, elegant solution that is obvious once revealed. Sadly, this is not the case. It is also to misunderstand the evolutionary and haphazard nature of the British constitution. Historically, our constitutional arrangements have been based on untidy compromise. It is conceivable that this is one more problem that will never be fully resolved to everyone's satisfaction. Indeed, it is worth pointing out that when Margaret Thatcher used Scotland as a test for the poll tax, it was the Scots who were unsettled; now it is the English.

A more useful question might be to ask what can be done to make its effects less contentious. One suggestion has been the creation of an English parliament, although there seems little public appetite for such an institution. Another solution is the Tory suggestion to limit voting rights of Scottish and Welsh MPs, but this rather undermines the point of a national parliament. A third option is to move to a much more federalised system, along the lines of Spain or Germany.

Our own more immediate preference would be to introduce an element of proportional representation into the British voting system. This would not answer the West Lothian question in itself, but would help smooth out some of the tensions of the present system - not least by increasing the Conservative representation in Westminster from north of the border. But whatever route forward is chosen, it will have to involve a healthy dose of compromise, in keeping with our traditions.