A wireless communications system, comprising: a base station (7a, 7b); a relay device (8a, 8b); and a terminal device (9a, 9b); wherein the terminal device is configured to transmit one or more access request messages of a first type to request uplink resources from the base station, wherein an access request message of the first type is a random access channel preamble selected from a first group of random access channel preambles, and if no response to the transmitted access request messages of the first type is received from the base station, to transmit an access request message of a second type, wherein an access request message of the second type is a random access channel preamble selected from a second group of random access channel preambles, different from the first group of random access channel preambles; the base station is configured to, responsive to an access request message of the first type received from the terminal device, transmit an allocation of uplink resources to the terminal device; wherein: the relay device is configured to ignore the access request message of the first type; the relay device is configured to, responsive to an access request message of the second type received from the terminal device, transmit a relayed access request message to the base station to request the base station to allocate uplink resources to the terminal device; and the base station is configured to, responsive to the relayed access request message from the relay device, transmit an allocation of uplink resources to the terminal device. a base station (7a, 7b); a relay device (8a, 8b); and a terminal device (9a, 9b); wherein the terminal device is configured to transmit one or more access request messages of a first type to request uplink resources from the base station, wherein an access request message of the first type is a random access channel preamble selected from a first group of random access channel preambles, and if no response to the transmitted access request messages of the first type is received from the base station, to transmit an access request message of a second type, wherein an access request message of the second type is a random access channel preamble selected from a second group of random access channel preambles, different from the first group of random access channel preambles; the base station is configured to, responsive to an access request message of the first type received from the terminal device, transmit an allocation of uplink resources to the terminal device; to transmit one or more access request messages of a first type to request uplink resources from the base station, wherein an access request message of the first type is a random access channel preamble selected from a first group of random access channel preambles, and if no response to the transmitted access request messages of the first type is received from the base station, to transmit an access request message of a second type, wherein an access request message of the second type is a random access channel preamble selected from a second group of random access channel preambles, different from the first group of random access channel preambles; the base station is configured to, responsive to an access request message of the first type received from the terminal device, transmit an allocation of uplink resources to the terminal device; the relay device is configured to ignore the access request message of the first type; the relay device is configured to, responsive to an access request message of the second type received from the terminal device, transmit a relayed access request message to the base station to request the base station to allocate uplink resources to the terminal device; and the base station is configured to, responsive to the relayed access request message from the relay device, transmit an allocation of uplink resources to the terminal device.