A mobile communications system for communicating data to/from mobile communications terminals, the system including: one or more base stations configured to provide a radio interface to communicate data with mobile communications terminals; and one or more mobile communications terminals configured to communicate data with the one or more base stations via the radio interface, and wherein a mobile communication terminal is arranged to use an uplink random access channel to transmit random access messages to the one or more base stations. A first mobile communications terminal is configured to communicate user data via the uplink random access channel by transmitting one or more of the random access messages at a selected timing within the uplink random access channel, the timing being selected by the first mobile communications terminal to represent at least part of the user data.