Chiltern's have operated for years a successful semi regional system. Three forces, five counties, two bases, with four control rooms. TFO's allowed to be responsible for the deployment of the aircraft.
All control rooms have a dedicated scramble line (land telephone) and one hailing talkgroup for all three forces. Crews's would be aware which aircraft was nearest and most effective.
This is local control with local knowledge making best use of the resource and deploying to incident where air support can enhance the situation using TFO;s experience.
All this control room will be is a very expensive call forwarding/delaying room.