A wireless telecommunication system that comprises a base station and a terminal device communicating over a radio interface. The radio interface supports a downlink control channel for conveying control messages from the base station to the terminal device and a downlink data channel (e.g. a physical downlink shared channel) for conveying higher-layer messages from the base station to the terminal device. The control messages convey information on resource allocations for the higher-layer messages on the downlink data channel. The terminal device is configured to receive a control message from the base station conveying an indication of allocated transmission resources on the downlink data channel and determine a validity period for the control-plane message. During the validity period for the control message the terminal device is configured to receive a plurality of different higher-layer messages from the base station on the downlink data channel using the allocated transmission resources.