It might be useful to know what that "device" is.
When I visited Swanwick two years ago London Info had a radar monitor positioned off to the side of the desk that the radio operator sat at, it showed the whole of the UK though so it would be difficult to find an individual aircraft on it. The operator would occassionally refer to it if he suspected an aircraft might be somewhere it shouldn't be, although obviously if an infringement was suspected it would quickly be refered to the relevant radar unit. Of course we all know there is no radar service and any identification of the aircraft is purely informal.