David Cameron: Airbrushed

David Cameron's airbrushed poster campaign has backfired - setting off an internet craze of hilarious spoof versions. On the mydavidcameron.com site jokers can adapt the "we can't go on like this" adverts to poke fun at the 15ft-high picture of the Tory leader. One shows his smoothed-over face with the words: "We can't go on like this. I'll cut my taxes, but not yours." Another replaces the picture with Harry Enfield's "Tim Nice But Dim"…