Why would the Met would need this capability considering....
there's nearly 1 to 1 ratio of CCTV cameras and London citizens? However, what about using the traffic lights to bring all the traffic in London to a stop during a blag? Once the alarm has been raised, all the traffic lights could remotely be turned to red thus impeding the getaway and forcing chummy to use bikes and scooters which would only be able to be driven on the pavement where chummy would be vulnerable to 'ave-a-go-heroes' who would think nothing of twatting them with their handbags or rolled up copies of The Times.
Hope this helps, Sir Bernard.