Scotland is already going its separate way. Not – yet at any rate – in terms of the UK’s constitution, but in terms of the Labour party. There is no papering over the cracks within the party on whether there should be an early vote on Scottish independence. The result is a mess that highlights Gordon Brown’s lack of authority in his own backyard. Worse, it treats an issue of genuine importance as a subject for opportunistic politicking.

Wendy Alexander, leader of the Scottish Labour party, started the ball rolling at the weekend with unexpected support for the idea of an early referendum. This is hard to reconcile with the views of Labour at Westminster, which strongly supports the Union and does not wish to embark on such a reckless course. On Wednesday the prime minister’s best effort at squaring the circle was to deny she had called for a referendum right now.

Textual analysis of Ms Alexander’s exact words misses the point. Her initiative has no merit. It was not the act of a listening party responding to a change of mood among the Scottish people. It was manifestly an effort to upset the buoyant mood of the minority Scottish National party government, which is enjoying high opinion poll ratings a year after taking office. But even on those terms it looks ineffectual. And given Labour’s unpopularity, the assumption that an early poll would be less likely to come down in favour of independence may well be flawed.

Instead, it has damaged Labour in London, compounding last week’s local election mauling, which weakened Mr Brown’s grip on party discipline. No wonder there is anger in government that Ms Alexander has exposed his lack of control over the Scottish Labour machine.

Putting Scottish independence back on the political agenda undermines the prime minister’s efforts to boost Britishness and invites a resurgence of English resentment at Scotland’s generous financial settlement. Moreover, whether the U-turn is good for Labour is nowhere near as important as whether an early vote on Scottish independence would be good for the UK. The answer is an emphatic No.

This newspaper believes that breaking up the Union would, at the least, diminish the UK’s weight on the international stage. If the Scottish people want to have a vote on independence, that is their democratic right. But any poll should come in response to a groundswell of opinion that suggests the question needs to be settled urgently, and after a serious debate on the economic and constitutional ramifications. That is not the case here.