Every now and then an unexpected souring in the public mood can quite suddenly overturn all the conventional assumptions about a nation's politics. We may be on the cusp of just such a seismic shift. I am not referring, though, to the outcome of the general election. If the polls are to be believed, the important vote will take place a few weeks later on the other side of the Channel. France's referendum on the European Union's constitutional treaty promises to transform not just French but British politics.

Europe has scarcely figured in Britain's election campaign. I did catch Michael Howard on Monday telling industrialists that the Conservatives would never join the euro and would declare all-out war on the bureaucrats of Brussels. Speaking from the same podium, Gordon Brown, the chancellor, seemed to be saying something remarkably similar. Look closely, meanwhile, at the finest print in the Liberal Democrats' policy platform and you will find only the merest hint of its federalist inclinations. That is about the sum of it.