Abstract: The strip is pre-creased to show the front, rear, sides, top and bottom of the packet, and provided with through cuts which combine with certain of the creases to create two pairs of top and bottom corner reinforcement tongues incorporated into the margins of the strip from which the sides of the box and lid are fashioned, each tongue being parted transversely by a cut parallel to and offset from the fold between the front and bottom faces of the box, and the front and top of the lid. The length of the top and bottom faces, measured across the packet from side to side, is reduced from the width of the front and rear faces of the box and the lid, and the top and bottom edges of the outermost side flaps of the box and lid are also cut short so as to remain distanced from the relative corners when the packet is folded into its final shape.