A method of communicating information between an intermediate element and a source element in a message-based communications system is provided where request and response messages being are sent via an intermediate element arranged to forward the messages to the appropriate element The method includes, at the intermediate element: prior to forwarding a received request message: determining the presence, in the received request message, of an indication of the information to be communicated and where present, adding a temporary identifier associated with the intermediate element to the message in such a way that the temporary identifier is included in the corresponding response message; and prior to forwarding a received response message: determining the presence of a temporary identifier associated with the intermediate element and, where present, replacing the temporary identifier with the information to be communicated to the source element.