A method of operating a first terminal device to transmit data to a second terminal device by performing device-to-device communication includes selecting radio resources, on which to transmit the data based on a priority status associated with the data, whereby certain radio resource are reserved for use in association with data classified as high priority. A method of operating the second terminal device to receive data from the first terminal device includes: receiving data from the first terminal device using the selected radio resources; determining if another terminal device is transmitting data on a radio resource which is not selected for transmitting data by the first terminal device and which is reserved for transmitting data classified as having a high priority; and, if so, stopping reception of data from the first terminal device on the selected radio resources and instead seeking to receive further transmissions from the other terminal device.