Here's the new Labour poster, launched at this morning's press conference. It's certainly an improvement on that disastrous Gene Hunt mock-up, and it picks up on a recurring criticism of the Conservatives, namely: who has time for Cameron's Big Society?

It was a point best made by Channel 4's Gary Gibbon at yesterday's manifesto launch. He asked: "What's the evidence that people want to be prised away from their telly or garden to do all this stuff?"

It's one thing to believe that a Conservative government would stimulate a dramatic rise in civic engagement, quite another to believe that this could act as a plausible substitute for the state.

David Cameron's hope that the Big Society will replace Big Government is reminiscent of the old Marxist belief that the state will "wither away" as a result of victorious socialism. We all know how that turned out.

Moreover, given that Cameron claimed, absurdly, that "big government" was responsible for the financial crisis and opposed the fiscal stimulus, it's reasonable to doubt his belief in the power of government.

With the polls still showing a lack of popular enthusiasm for Cameron, the Tories clearly need a big idea to woo the electorate. But I'm really not sure the "Big Society" is it.

Join us for the first TV leaders' debate this Thursday.