I believe it was made by Jackson Brothers, Knottingley: date, post WW2. I have a smoke iridised example and I have seen several others in different colours, all lightly iridised (one of which - I seem to recall - had talcum powder inside and was labelled accordingly). Mine has JBK entwined, moulded on the base and a Reg No which appears to be 905918.
(Item referenced in "A Century of Carnival Glass").
Glen