 Post @-@ war , Devonport Dockyard was kept busy refitting aircraft carriers such as the Ark Royal and , later , nuclear submarines while new light industrial factories were constructed in the newly zoned industrial sector attracting rapid growth of the urban population . The army had substantially left the city by 1971 , with barracks pulled down in the 1960s , however the city remains home to the 42 Commando of the Royal Marines . 
