There was always a 'ground' frequency but it was operated by the assistant for vehicles only thus relieving the person talking to aircraft of some of the workload.
Having said that, the 'normal' system is for just one controller to handle all aircraft calls; it's only when an airfield gets really busy you need to 'split' the functions.
At Farnborough for instance, a GMC position is only used during the Air Show, other times one controller handles startups, clearance delivery, co-ordination with approach, taxy clearance, departures and vehicles operating on the airfield.
Last edited by chevvron; 28th Feb 2018 at 12:45.