Is it possible to have a debate about liberty based on fact? Or are questions of freedom and citizenship ultimately about ideals and perceptions?

Times Columnist David Aaronovitch has tracked down a fiction being used to campaign against CCTV (the security cameras – not Chinese telly). It is the oft-quoted ‘fact’ that the average Briton is captured on CCTV 300 times every day. My Germany-dwelling brother cited it just this weekend during a trip to London. But it ain’t true. Indeed, it is literally based on a made-up story.

The academics who created the statistic did so by imagining a hypothetical person’s journey through an imaginary city-scape. It was part of a report written back in 1999 to stimulate debate and was hostile to CCTV. But it has long passed into the land of newspaper cuttings, or their digital equivalent, Google search.

Aaronovitch takes a less hostile view of CCTV, which is why he bothered to check the ‘fact’. He has also just written a book on conspiracy theories, so he is in a myth-busting, empiricist mood. So he may be ‘biased’ but this is a wonderful bit of fact-checking and shows how these things can go viral.

I think that the debate around Privacy on the Internet is similarly subject to myth and confusion. We are warned of a Big Brother digital state and yet we happily surrender our details on a daily basis. Does government and business really know much more about us than before, or is it simply more easily accessed and passed around?

The politics of liberty are going to become increasingly important as this century trundles on. The magnificent grandstanding of people like Henry Porter has touched a raw nerve but if the debate is to move beyond fear and loathing than we need facts not fiction.

David Aaronovitch is speaking at Polis on May 7th.