You could say that the Conservatives have never had an easier target. All the important economic news - about growth, inflation, the public finances and the rest - in this week's Budget will be somewhere on a spectrum from ominous to bad. Later if not sooner, taxes are going to have to rise.

The best Alistair Darling can probably do is grab a few diversionary headlines. You know the sort of thing: chancellor gets tough on binge drinking; Darling goes green in crackdown on gas guzzlers; energy bosses told to slash soaring fuel bills.