Mary ##sworth worked at Drakelow Underground Factory from 1943 - 1945 . Aged 20 , she analysed uranium in its laboratory for Bristol Hercules engines . Now ##more , the great grandmother has visited the site in 1947 . It was one of several underground factories used to manufacture military explosives .
Mary Cartwright worked at Drakelow Underground Factory from 1943-1945 . Aged 20 , she analysed metal in its laboratory for Bristol Hercules engines . Now 91 , the great grandmother has revisited the site in Kidderminster . It was one of 26 underground factories used to produce military parts .