WW1 Gas Light & Power Supply on war service badge

A scarce First World War period 'Gas Light & Power Supply On Public Service war service badge'; gilded brass large circular example, the title surround inlaid with blue enamel, the centre depicting the united emblems of England, Scotland and Ireland, a Rose, Thistle and Shamrock, on white enamel ground, the reverse with maker's detail 'Vaughtons Ltd Birmingham'. Good condition, retaining original buttonhole horseshoe fitting, enamel intact with very minor service wear. Diameter 28mm.