A communications device acting as a relay device at the radio link control, RLC, layer configured to communicate with a transmitting node operating with a mobile communications network and a receiving node operating with the mobile communications network, the communications device acting as the relay device comprising receiver circuitry configured to receive signals representing protocol data units formed from one or more service data units via a first wireless access interface at the RLC layer from the transmitting node according to a first automatic repeat request process for transmission to the receiving node, transmitter circuitry configured to transmit data conveyed by or representing the received protocol data units via a second wireless access interface at the RLC layer to the receiving node according to a second automatic repeat request process, controller circuitry configured to control the transmitter circuitry to transmit the signals and to control the receiver circuitry to receive the signals to transmit, and a buffer configured to store data conveyed by or representing the received protocol data units for transmission to the receiving node according to the second automatic repeat request process, wherein either the buffer is a combined transmission/reception buffer of a single RLC entity or the buffer is split across an independent transmission RLC entity and an independent reception RLC entity, wherein if the data representing a number of the received protocol data units or number of bytes stored in the buffer exceeds a predetermined threshold, the controller circuitry is configured in combination with the transmitter circuitry and the buffer to transmit to the transmitting node an indication that data representing the received protocol data units as a number of protocol data units or the number of bytes stored in the buffer exceeds the predetermined threshold. receiver circuitry configured to receive signals representing protocol data units formed from one or more service data units via a first wireless access interface at the RLC layer from the transmitting node according to a first automatic repeat request process for transmission to the receiving node, transmitter circuitry configured to transmit data conveyed by or representing the received protocol data units via a second wireless access interface at the RLC layer to the receiving node according to a second automatic repeat request process, controller circuitry configured to control the transmitter circuitry to transmit the signals and to control the receiver circuitry to receive the signals to transmit, and a buffer configured to store data conveyed by or representing the received protocol data units for transmission to the receiving node according to the second automatic repeat request process, wherein either the buffer is a combined transmission/reception buffer of a single RLC entity or the buffer is split across an independent transmission RLC entity and an independent reception RLC entity, wherein if the data representing a number of the received protocol data units or number of bytes stored in the buffer exceeds a predetermined threshold, the controller circuitry is configured in combination with the transmitter circuitry and the buffer to transmit to the transmitting node an indication that data representing the received protocol data units as a number of protocol data units or the number of bytes stored in the buffer exceeds the predetermined threshold.