David Marquand (Oxford, oD author): From 600 miles away, British politics seem more than usually dismal, and more than usually petty. The sight of Labour MPs running around complaining about Brown's faults only a year after they gave him the leadership on a plate is deeply unedifying, to put it at its lowest. Nothing new has happened to his character or style since he became leader. He is still the person he has been for the last 20 years and more. If his MPs have now changed their minds about him that tells us more about their gutlessness than about his inadequacies. If he's unfit for the job now, he was unfit a year ago. If he was fit then, he's fit now.

But Brown's personality is not the real issue in any case. The first and most obvious point to make about Glasgow East is that it happened in Scotland, and that the Scottish National Party won! I don't think it was a vote against the Union, but I do think it was a vote against the way in which the devolution legislation was framed. New Labour was trying to have its cake and eat it - to appease the manifest Scottish demand for Home Rule, while maintaining the sovereignty of the Westminster Parliament and the inequitable absurdities of the Barnett formula on finance. It was always likely that this would blow up in Labour's face sooner or later; and in Glasgow East it did so with an almighty bang.

I doubt if many people, on either side of the Border, want to see the Union break up; but unless Labour discovers reserves of imagination and political intelligence far beyond anything they have displayed so far, we may well stagger into break up, rather in the way that the Soviet Union staggered into a break up after the anti-Gorbachev coup.

But the second point is that, though the break-up of the Union would be a pity, it wouldn't be a disaster. All over Europe the artificial, 'modern' nation-states, created in the eighteenth and nineteenth centuries, are fragmenting under the pressures of the 'post-modern' era we now live in. Ancient, 'pre-modern' provinces, regions, city states and linguistic communities are re-emerging from the deep freeze into which they were forced during the heyday of modernism. The consequences have sometimes been appalling - look at the former Yugoslavia. But in member-states of the supranational EU, they have been held in check by the quintessentially post-modern institutions and norms of the Union. Flickering on the horizon, I think, is the vision of a Europe des Regions. It would be a nice irony if the UK, the first unmistakably modern European state, were to be the chief author of such a Europe.

The third point is that centralist, statist, unimaginative, heavy-handedly modern social democracy is about as ill-fitted to cope with this post-modern fragmentation as the CPSU was to cope with the fragmentation of the Soviet Union. I don't know if any mainstream British politician could do better. But Alex Salmond might, just might, have the wit and cunning to steer Scotland in a post-modern, post-nationalist direction; and who knows, a de facto, unacknowledged, tacit coalition between a post-nationalist Salmond and a post-Thatcherite Cameron might discover a way through.

Still to come in the Labour after Brown series this week: Gerry Hassan asks whether the party can come to terms with the new progressive imagination emerging in Scotland and Wales.