This open area was used for troop training. Here the soldiers would muster and parade.This was a very dangerous place to be when the fort was under bombardment and a safer method of communication between the soldiers' barack rooms and their action stations on the main ramparts was provided by three separate tunnels beneath the parade. Each tunnel also lead to a caponier for flank defence of a branch of the main ditch. A spiral stair from each tunnel gave access to the mortar batteries and on to the firing steps and base of the ramparts.
Some later buildings on the parade consisted of a recreation room and by 1912 a set of large troop stables were built close to the west ramparts. Just prior to World War Two the parade was filled with ten shell stores for anti-aircraft shells. At this time Fort Nelson was converted to an area magazine, supplying ammunition to gun batteries along the south coast.
All but two of these shell stores were demolished to develop the fort as part of the Royal Armouries Museum of Artillery.