[HenryLB]

I think a major problem lies not just with the credulous who indulge these ideas but also with the way that information is disemminated nowadays. Everyone now has such an understanding of the media and how it shapes opinion that its manipulation is second nature to almost every large organisation. Whole departments exist to "spin", not just in politics (where it is most obviously prevalent) but also in corporations, interest groups and state structures.

Think of the police in the wake of the Jean Charles de Menezes shooting. Their PR wonks immediately began a whispering campaign against a wholly innocent victim: he was wearing a bulky jacket, he jumped the barrier and ran to the train, he had a dodgy history. All bollocks, and they knew it, and - which is worse - they must have known it would come out that it was a tissue of lies. But they went ahead and fabricated the information anyway because they knew it would give them the critical breathing space to get the story from page one to page five. A small but rather ill-won victory.

All this creates an atmosphere of distrust, and the more fertile minds naturally leap to the most extraordinary conclusions.