As usual at this time of year, it’s election day in Britain, with local council elections across much of England. As I explained last year, these polls are intrinsically “no more important than local elections in Australia”, but commentators invest them with national significance: “If the political class, desperate for guidance of some sort, thinks these elections are important, then they are.”

Like last year, the big national issue is the transition of power in the Labour Party. Ten years on from his first election, Tony Blair is on the point of announcing his retirement, and will hand over rather unwillingly to chancellor of the exchequer Gordon Brown.

It’s not clear that this will do anything for his party’s fortunes.

Although Blair is personally unpopular within Labour in a way Brown is not, there is little evidence that the electorate at large draws much of a distinction between them. Blair’s supporters have tried hard to convince David Miliband to run against Brown, but he evidently prefers to hold himself in reserve.

The most interesting poll today is in Scotland, where the devolved Scottish parliament is up for election as well as local authorities (ditto for Wales, but it seems less controversial). Brown is himself Scottish – more so than Blair, who was born there but regards himself as English – and Scotland has been a Labour stronghold for many years.

But the Scottish parliament is elected by proportional representation (strictly a hybrid system, but largely proportional), so no single party can win a majority. In a four party system, Labour currently governs in coalition with the Liberal Democrats: they have 67 seats between them, as against 27 for the Scottish Nationalists, 18 Conservatives, and 17 for minor parties and independents.

The Scottish Nationalists have been gaining in the opinion polls, and the consensus is that they will emerge as the largest party (Wikipedia has a good compilation of poll results). If so, there will probably follow a period of bargaining as they try to put together a majority coalition, with the Lib Dems and the Greens as their most likely partners.

The Nationalists have promised a referendum on Scottish independence, but none of the other parties are at all keen on the idea. The irony is those who are most opposed to it – the Tories and their allies – also have the most to gain from removing Scottish MPs from Westminster, and especially from the discomfort it would cause Brown.

The union of England and Scotland is now 300 years old, but it has rarely looked so fragile. It may take another term, but sooner or later the Scots will probably get to vote on whether they want to go it alone.