A cable locking device comprising: a housing with a cable passage; a reel at least partially disposed in the housing and rotatable in a first, cable tightening direction and a second, cable loosening direction; a cable having a first end portion fixed to the reel and a second end portion extending outward through the cable passage in the housing; at least one clamp member (141, 142) disposed in the housing, the at least one clamp member (141, 142) defining at least a portion of the cable passage, and being movable between a clamping position in which the at least one clamp member (141, 142) engages a portion of the cable disposed in the cable passage to prevent movement of the cable within the cable passage in at least an outward direction, and a releasing position in which the at least one clamp member (141, 142) permits movement of the cable within the cable passage in the outward direction; and a locking mechanism assembled with the housing and movable between a locked position and an unlocked position, the locking mechanism including a reel securing portion and a clamp member securing portion, wherein when the locking mechanism is in the locked position, the reel securing portion secures the reel against rotation in the cable loosening direction, and wherein when the locking mechanism is in the unlocked position, the clamp member securing portion secures the at least one clamp member (141, 142) in the releasing position characterised in that: the locking mechanism comprises a user manipulable lockout member connected to the housing, the lockout member being movable to a first position to move the locking mechanism to the locked position, and movable to a second position to move the locking mechanism to the unlocked position; and at least one of the lockout member and the housing comprises at least one lock aperture (117, 157), wherein when the lockout member is in the first position, insertion of a padlock shackle through the at least one lock aperture (117, 157) prevents movement of the lockout member to the second position. a housing with a cable passage; a reel at least partially disposed in the housing and rotatable in a first, cable tightening direction and a second, cable loosening direction; a cable having a first end portion fixed to the reel and a second end portion extending outward through the cable passage in the housing; at least one clamp member (141, 142) disposed in the housing, the at least one clamp member (141, 142) defining at least a portion of the cable passage, and being movable between a clamping position in which the at least one clamp member (141, 142) engages a portion of the cable disposed in the cable passage to prevent movement of the cable within the cable passage in at least an outward direction, and a releasing position in which the at least one clamp member (141, 142) permits movement of the cable within the cable passage in the outward direction; and a locking mechanism assembled with the housing and movable between a locked position and an unlocked position, the locking mechanism including a reel securing portion and a clamp member securing portion, wherein when the locking mechanism is in the locked position, the reel securing portion secures the reel against rotation in the cable loosening direction, and wherein when the locking mechanism is in the unlocked position, the clamp member securing portion secures the at least one clamp member (141, 142) in the releasing position characterised in that: the locking mechanism comprises a user manipulable lockout member connected to the housing, the lockout member being movable to a first position to move the locking mechanism to the locked position, and movable to a second position to move the locking mechanism to the unlocked position; and at least one of the lockout member and the housing comprises at least one lock aperture (117, 157), wherein when the lockout member is in the first position, insertion of a padlock shackle through the at least one lock aperture (117, 157) prevents movement of the lockout member to the second position. the locking mechanism comprises a user manipulable lockout member connected to the housing, the lockout member being movable to a first position to move the locking mechanism to the locked position, and movable to a second position to move the locking mechanism to the unlocked position; and at least one of the lockout member and the housing comprises at least one lock aperture (117, 157), wherein when the lockout member is in the first position, insertion of a padlock shackle through the at least one lock aperture (117, 157) prevents movement of the lockout member to the second position.