ATC Radar
Air Traffic Control can be basically spit into two. Approach/Radar and Tower/Ground. The Approach/Radar section usually are looking at their displays and are (often) never visual with who ever they are talking to. This service can be done from anywhere in the world, never mind just Liverpool.
The Tower/Ground service, well, that is usually different, as the controller usually finds it helps to look out of the windows in the tower.