In 1974 was issued white ones and black ones, then we had to blacken and bull the white ones. Others were issued brown ones. No reason except what was in the store at time and sizes. Still have them on my kit issue list (formerly AF 1157) and when i finally demob will hand them in with the trousers, lightweight, shirts, wooly pully, gloves knitted, vests and drawers cellular, green long johns, Parasmock etc