It is provided a method performed by a key device for supporting duress signalling. The method comprises the steps of: determining that a user is under duress; entering a wait state after the step of determining that a user is under duress; exiting the wait state and establishing a communication channel with a lock device, the communication channel being intended to be used for access control signalling; generating a duress signal; and transmitting, over the communication channel, the duress signal to the lock device.