Abstract: A plastic lid is provided for an open topped generally circular container having an outwardly directed lip encircling the open top of the container. The lid comprises a rim of generally annular shape to cooperate with the outwardly directed lip of the container and a squat generally cylindrical section extending from an inner periphery of the rim to a closure wall at its operatively inner end to form a plug type of closure adapted to form a seal with an inner periphery of the container. The lid has at least one locking member that is an endless locking ring connected to the rim by way of one or more integral frangible connecting elements. The locking member is adapted to operatively cooperate with the lip of the container such that fracturing of one or more of said integral frangible connecting elements occur attempted removal of the lid from the container.