A conference call is established in response to receiving a request 4 from a first communication terminal 3a. The request 4 preferably is an SMS or MMS and comprises one or more identifiers 5, 6, 7, e.g. telephone numbers, relating to a plurality of other communication terminals 3b-3d. A conference call server I allocates a conference call channel and an associated identifier, such as a telephone number. Messages 10a-10c alerting the conference participants are then sent to the other communication terminals 3a-3c, each message including the identifier associated with the conference call channel. Access to the conference call may be restricted to authorised users by compating identifiers, such as CLIs, of incoming callers to the identifiers provided in the request 4 and allowing access only if there is a correspondence or match. In the event that an incoming caller has withheld their CLI, or it is otherwise nondeterminable, access is refused and a message may be sent reminding conference participants who have yet to join the conference call not to withhold this information. Alternatively, the server calls the participants at the appropriate time.