Abstract: The invention is in respect of a lock having a body and an actuator arrangement which is displaceable relative to the body between an inoperative condition and an operative condition. The actuator arrangement is capable of operating a device such as a locking mechanism or the like only when in its operative condition. The lock further includes non-mechanical key identification means. The lock further includes retaining means for retaining the actuator arrangement releasably in its inoperative condition. The identification means and operative in response to a signal received therefrom to permit displacement of the actuator arrangement to its operative condition. The actuator arrangement typically includes an inner member, an outer member and a coupling whereby the inner and outer member are coupled together to permit relative longitudinal displacement between the inner and outer member and inhibit relative rotational movement.