The British Great Coat, Dismounted 1940 Pattern, was a wool overcoat worn by British military personnel during World War II. 

The coat was made of heavy, khaki-colored wool, with a double-breasted front, wide lapels, and two large pockets. The coat had a waist belt and a buttoned half-belt in the back, allowing for an adjustable fit. 

The coat was manufactured by a number of different companies during the war, including Durigo Manfg. Ltd, which is likely the manufacturer of the specific coat you are referring to. The coat was commonly dated with the year of manufacture on the label, which in this case is "1943."