A closure comprising a solid colour spout and a transparent overcap is adapted to be sealed to a container neck by means of a double-sided foil. The overcap has a depending valve, which engages with the spout to hold these components together prior to assembly to the container. The spout has a flange adapted to seat on a rim of the container neck and an annular wall that is received within the container neck. The foil is welded to the flange and is also used to weld the closure to a rim of a container neck of standard threaded design. The overcap can screw to an external thread on the container neck. The primary ex-factory seal is provided by welding the assembled closure to the neck. The secondary seal is provided by the engagement of the overcap valve with the spout. The invention discloses an improved method of assembly.