Group handover in a cellular communications network

A cellular communications system permits handover of a group of mobile stations (15) having like characteristics from a base station (13) operating in one type of network e.g. UMTS to a base station (16) operating in a different type of network e.g. GSM, or from a first carrier frequency to a second carrier frequency both being supported by the same base station, thereby relieving congestion in an overloaded cell by handing over a group of calls to an under-loaded one. The invention has the benefits of enabling such a handover with the minimum of signalling overhead.