The guy that wrote it wanted a suitably shock-horror piece so he went to the main street of a shitty part of London, counted every CCTV camera he could see everywhere including ones inside all the betting shops, off-licences, pawn shops, cheque cashing places, and so on - all lovely totally-not-dodgy businesses I'm sure - and then multiplied up by the total amount of roads in the UK.
If the figures were accurate then every single-track road that's basically just a cow path with tarmac sprayed over it would have a CCTV camera every four car lengths, which is clearly not the case.