SECURITY LOCK

This invention concerns a security lock for use with a lock unit. The security lock has a base, a casing in which the base is, in use, received, an elongate locking bolt, biasing means for urging the locking bolt towards its inoperative position, an externally accessible operating member for moving the locking bolt and a locking mechanism which is used to lock the bolt in its operative position. A securing mechanism is operable between a locked state in which the base and casing are locked to each other and a released state in which the base and casing are released from each other. A securing element is held captive such that it remains in position irrespective of whether the securing mechanism is in its locked or released state.