I did actually do a quick legal analysis of what was wrong with that scene legally and practically.
First for it to work the CCTV cameras clearly had to have had real-time human surveillance behind them not simply be recording for future reference which is a both a statement about the types of cameras used (ie they probably couldn't have been made to work in that way) and also about the law in that everyone passing into view would have potentially had both their DPA and their RIPA rights breached. Most of those cameras will actually have been owned and operated by the London Borough of Lambeth who as a Labour-controlled and very stroppy council will be unlikely to take kindly to Central Government hijacking their property and putting them in breach of a DPA/RIPA claim. There was no grounds to order directed intrusive surveillance of John (well, barring the illegal handgun,which he didn't actually have on him at the time,but it would have been the obvious defence to run if he had made a complaint under RIPA) to say nothing of everyone else who'd have been caught by those cameras eg Sally Donovan and no evidence that anyone with the formal power to order surveillance (police of Lestrade's rank or above, JPs, trading standards officers, etc) had made a formal determination.
no subject
First for it to work the CCTV cameras clearly had to have had real-time human surveillance behind them not simply be recording for future reference which is a both a statement about the types of cameras used (ie they probably couldn't have been made to work in that way) and also about the law in that everyone passing into view would have potentially had both their DPA and their RIPA rights breached. Most of those cameras will actually have been owned and operated by the London Borough of Lambeth who as a Labour-controlled and very stroppy council will be unlikely to take kindly to Central Government hijacking their property and putting them in breach of a DPA/RIPA claim. There was no grounds to order directed intrusive surveillance of John (well, barring the illegal handgun,which he didn't actually have on him at the time,but it would have been the obvious defence to run if he had made a complaint under RIPA) to say nothing of everyone else who'd have been caught by those cameras eg Sally Donovan and no evidence that anyone with the formal power to order surveillance (police of Lestrade's rank or above, JPs, trading standards officers, etc) had made a formal determination.