A wireless communications system (110, 160, 170, 180, 190, 200, 220) comprising: a first stack of a first wireless communications protocol; a second stack of a second wireless communications protocol; a wireless interface arranged to transmit and receive wireless signals, and wherein the wireless interface is useable by the first stack and the second stack; and an arbitrator (150, 162, 176, 181, 206) in communication with the first stack and the second stack, wherein the first stack is configured to determine a first priority associated with a current message to be transmitted or received by the first stack using the wireless interface, the second stack is configured to determine a second priority associated with a current message to be transmitted or received by the second stack using the wireless interface, and wherein the arbitrator is configured to control which one of the first stack and the second stack can use the wireless interface to transmit or receive the current message, wherein the first stack is configured to dynamically determine the first priority based on a current status of the first stack and a type of the current message to be transmitted or received by the first stack, the second stack is configured to dynamically determine the second priority based on a current status of the second stack and a type of the current message to be transmitted or received by the second stack and the arbitrator is configured to control which one of the first stack and the second stack can use the wireless interface to transmit or receive the current message based on which of the first priority and the second priority is higher. a first stack of a first wireless communications protocol; a second stack of a second wireless communications protocol; a wireless interface arranged to transmit and receive wireless signals, and wherein the wireless interface is useable by the first stack and the second stack; and an arbitrator (150, 162, 176, 181, 206) in communication with the first stack and the second stack, wherein the first stack is configured to determine a first priority associated with a current message to be transmitted or received by the first stack using the wireless interface, the second stack is configured to determine a second priority associated with a current message to be transmitted or received by the second stack using the wireless interface, and wherein the arbitrator is configured to control which one of the first stack and the second stack can use the wireless interface to transmit or receive the current message, wherein the first stack is configured to dynamically determine the first priority based on a current status of the first stack and a type of the current message to be transmitted or received by the first stack, the second stack is configured to dynamically determine the second priority based on a current status of the second stack and a type of the current message to be transmitted or received by the second stack and the arbitrator is configured to control which one of the first stack and the second stack can use the wireless interface to transmit or receive the current message based on which of the first priority and the second priority is higher.