A communications device for transmitting a message to an infrastructure equipment of a mobile communications network, the communications device comprising a transmitter configured to transmit signals via a wireless access interface provided by the infrastructure equipment, a receiver configured to receive signals from the infrastructure equipment via the wireless access interface, and a controller configured to control the transmitter and the receiver to transmit and/or receive the signals, the controller being configured with the receiver to receive an indication of an allocation of physical resources of the wireless access interface providing a plurality of different physical channels of different types, each of the different types of physical channels being defined for transmitting messages in accordance with a different priority level using a contentious access technique, the allocation of the physical resources being dependent upon the priority of the message and the contentious access technique, and the controller is configured with the transmitter to identify, based on a type of one or more messages, a relative priority for transmitting the one or more messages to the infrastructure equipment, to select one of the physical channels in accordance with the identified relative priority, and to transmit the one or more messages to the infrastructure equipment via the selected physical channel, wherein the one or more messages are transmitted via the selected physical channel in accordance with the contentious access technique determined for the selected physical channel provided by the received indication, and a first type of message is triggered by an event and is associated with a first priority level, and a second type of message is triggered periodically and is associated with a second priority level lower than the first priority level. a transmitter configured to transmit signals via a wireless access interface provided by the infrastructure equipment, a receiver configured to receive signals from the infrastructure equipment via the wireless access interface, and a controller configured to control the transmitter and the receiver to transmit and/or receive the signals, the controller being configured with the receiver to receive an indication of an allocation of physical resources of the wireless access interface providing a plurality of different physical channels of different types, each of the different types of physical channels being defined for transmitting messages in accordance with a different priority level using a contentious access technique, the allocation of the physical resources being dependent upon the priority of the message and the contentious access technique, and the controller is configured with the transmitter to identify, based on a type of one or more messages, a relative priority for transmitting the one or more messages to the infrastructure equipment, to select one of the physical channels in accordance with the identified relative priority, and to transmit the one or more messages to the infrastructure equipment via the selected physical channel, wherein the one or more messages are transmitted via the selected physical channel in accordance with the contentious access technique determined for the selected physical channel provided by the received indication, and a first type of message is triggered by an event and is associated with a first priority level, and a second type of message is triggered periodically and is associated with a second priority level lower than the first priority level.