The big 'but' however is whether such attacks win votes. So far the commentators are divided, but you can discount the Tories' claims to be 'happy' with the story –they would say that, wouldn't they?
The strategy to depict Cameron as a chameleon was devised by Gordon Brown and his team, and fitted exactly with what Labour's notorious focus groups have been saying about the Tory leader. The Brown team drew strength from the Chancellor's Budget jibe about adding VAT to flip-flops – the reference to Dave's beachwear and his tendency to shift between policies has been remembered long after the contents of the Budget itself.
The chameleon broadcast was 100 per cent negative, and as such likely to be much more effective than Patricia Hewitt's claims that the NHS has had its 'best year ever'. Negative, or positive, campaigns only work when they hit a nerve with the public. Which is why the Tories' famous 1997 Demon Eyes campaign backfired. The public may have had doubts and questions about Tony Blair, but it was a leap of faith to make him a demon.
The local elections themselves, for which we vote on 4 May, are of course a massive test for Cameron and his new Conservatives. And
so far his team has not been doing the most important thing: to diminish expectations. Ridiculous photocalls, including one on top of an iceberg, haven't helped.
Ultimately it is how the election results are reported that matters, and I sense I've read a few too many articles about the Conservatives winning 40 per cent of the vote. Given that last week's poll in The Daily Telegraph had the Tories on 33 per cent, 40 per cent would be a sensational result – and even I would be paying a visit to the bookies for a flutter on Cameron to be PM.
My guess is that the main story to follow from the elections will be the disturbing rise of the British National Party – and we will be none the wiser as to whether Labour's party political broadcast did its job.