A method for initiating a call in a communications system; in which the communications system comprises: a mobile communications device connected in a mobile communications network; in which the mobile communications device is allocated an identifier for a mobile communications service provided by a mobile communications service provider and a second identifier for a second communications service; in which the mobile communications device is associated with a billing account for the mobile communications service; in which the method comprises: receiving, at a switch over a data connection from the mobile communications device, a request to initiate a call using the second communications service; in which the received request comprises the second identifier; the method characterized by: adding, at the switch, the mobile identifier to the received request and forwarding via a further communications network the request comprising both the second identifier and the mobile identifier to a communications service provider; allocating to a billing account for a third communications service, a charge relating to the call using the second communications service. a mobile communications device connected in a mobile communications network; in which the mobile communications device is allocated an identifier for a mobile communications service provided by a mobile communications service provider and a second identifier for a second communications service; in which the mobile communications device is associated with a billing account for the mobile communications service; in which the method comprises: receiving, at a switch over a data connection from the mobile communications device, a request to initiate a call using the second communications service; in which the received request comprises the second identifier; the method characterized by: adding, at the switch, the mobile identifier to the received request and forwarding via a further communications network the request comprising both the second identifier and the mobile identifier to a communications service provider; allocating to a billing account for a third communications service, a charge relating to the call using the second communications service. receiving, at a switch over a data connection from the mobile communications device, a request to initiate a call using the second communications service; in which the received request comprises the second identifier; the method characterized by: adding, at the switch, the mobile identifier to the received request and forwarding via a further communications network the request comprising both the second identifier and the mobile identifier to a communications service provider; allocating to a billing account for a third communications service, a charge relating to the call using the second communications service. adding, at the switch, the mobile identifier to the received request and forwarding via a further communications network the request comprising both the second identifier and the mobile identifier to a communications service provider; allocating to a billing account for a third communications service, a charge relating to the call using the second communications service.