Following a collapse of part of the fortifications in 1807 another application was made for revetting to take place. Nevertheless, at the end of the
Napoleonic Wars the Citadel remained unfinished; it was not until the start of the
Crimean War in 1853 that work resumed on completing and revetting the ditches. At the same time, some of the existing
casemates were adapted to provide barracks accommodation for 500 men.
By 1860 the Citadel was entered, via a
drawbridge over the ditch, through a gate on the eastern side; a tunnel then led through the rampart into the fort by way of the main guard room.
Between 1860 and 1874
outworks were added. By now, within the
ramparts, the Citadel contained barracks, stores and
magazines arrayed around a large parade ground.
[5] The bomb-proof Officers' Quarters and Mess, built by Major
William Jervois in 1860, was designed in part to be able to function as a defensible keep in the event of the Citadel being stormed by the enemy.
[7]
After 1890 the Citadel ceased to have a defensive role and functioned instead as a large barracks and
mobilisation centre, with additional hut accommodation provided for up to 900 soldiers in total. In 1956 the Citadel was handed over to
HM Prison Service; it served successively as a
Borstal, a Youth Custody Centre and a
Young Offender Institution.
[6]