Container closure cap and container closure

In combination,

• A tamper indicating overseal comprising:
• a top wall,
• an annular top wall skirt attached to a periphery of the top wall,
• a tamper-detecting band radially spaced from and overlying the top wall skirt, and
• a frangible connection between the tamper-detecting band and the top wall skirt and
• B. a threaded container closure plug received in a container opening and comprising:
• a rotational axis about which the plug is rotated as it is screwed into or unscrewed from the container opening, and
• an annular groove formed about the rotational axis of the plug;
• wherein the overseal further comprises a plurality of locking members attached to the top wall skirt and circumferentially distributed thereabout so as to initially project inwardly and downwardly with respect to the top wall for engagement of the overseal with the container closure plug;
• the locking members being movable by such engagement to a second position projecting inwardly and upwardly towards the top wall, thereby to lock the overseal to the container closure plug;
• wherein each locking member comprises a distal portion configured such that in the inwardly and upwardly projecting position of the locking member, the distal portion lockingly engages within the annular grooves so that the locking members lie with their axes substantially parallel or at the shallow angle to the rotational axis of the plug and thereby resist removal of the overseal from the plug.