Lid for drinks container

Claim 1

A circular lid for a container of liquids, which lid is vacuum formed in thin extruded sheet plastic; wherein the lid includes a depressed well, which is surrounded by a raised ridge which is in turn surrounded by a depressed trough, which is in turn surrounded by a rim, each of said well, ridge, trough and rim being substantially circular; the bottom of the well and the top of the ridge each being flat; the side walls and top of the ridge being of such height and radial width that a person's thumb and forefinger can be easily placed well in contact with the respective side walls, one inside and one outside the ridge; the plane of the bottom of the well being at a small angle to the plane of the top of the ridge, such that the height of the side walls of the ridge varies around the circumference of the ridge; there being a cut or slit in the trough outside the ridge; the orientation at which said walls are the highest with respect to the bottom of the well being substantially coincident with the orientation at which the said cut is formed; said cut or slit being so placed that when a finger and thumb are in place on either side of said ridge, one of said finger and thumb, upon squeezing the ridge, enters the cut or slit and thereby tends to spread the cut or slit so that liquid may be poured therethrough; and said cut or slit being out of line with the axis of extrusion or grain of the extruded sheet.