Coming soon to a nation near you:
It’s not a silver bullet. Take the example of the Brixton bomber [David Copeland, who planted three bombs in London in 1999]. The police gathered all the CCTV footage from all the cameras in Brixton, but it took 50 detectives over 20 days to plough through all the tapes. As it turned out, forensic evidence from the bag he was carrying proved crucial.