Between 1876 and 1878, plans were made to create a magazine in the South Entrance complex to serve St Martin’s Battery - a new battery of coast artillery situated on the other side of Centre Road. Originally the magazine was going to be placed in the pre-existing gun-room 1. These plans were, however, changed and the Magazine was constructed on the northern side of the passage linking the Southern Gatehouse with the gunrooms defending the South Entrance Ditch, it was completed in 1877. (location accurate to the nearest 2m based on available information)