Interesting:

London has 10,000 crime-fighting CCTV cameras which cost £200 million, figures show today.

But an analysis of the publicly funded spy network, which is owned and controlled by local authorities and Transport for London, has cast doubt on its ability to help solve crime.

A comparison of the number of cameras in each London borough with the proportion of crimes solved there found that police are no more likely to catch offenders in areas with hundreds of cameras than in those with hardly any.