A closure (22) for a bottle (20) containing carbonated beverages. The closure (22) comprises an inner part (28) and an outer part (24). The inner part (28) is adapted to receive a portion of a finish of the bottle (20) and includes a plurality of outwardly extending first cam surfaces (32) that are obliquely angled to the longitudinal axis of the closure (24). The outer part (24) is adapted to fit substantially over the inner part (28), the outer part (24) including a plurality of inwardly extending second cam surfaces (34) that are obliquely angled to the longitudinal axis of the closure (22). The outer part (24) is movable relative to the inner part (28) between a closed position in which at least a portion of the outer part (24) urges at least a portion of the inner part (28) against the neck to resist disengagement of the inner part (28) from the finish and an open position in which the inner part (28) allows disengagement of the inner (28) part from the finish. When the outer part (24) is in the closed position: applying a longitudinally directed force to the outer part (24), relatively away from the inner part (28), causes the outer part (24) to move longitudinally relative to the inner part (28) towards the open position as the first cam surfaces (32) travel relatively longitudinally away from the second cam surfaces (24); and twisting the outer part in a first direction about the longitudinal axis relative to the inner part (28) drives the inner and outer parts longitudinally towards the open position as the second cam surfaces (34) travel relatively along the first cam surfaces (32).