Fort Clarence today consists of a large red brick tower that overlooks the River Medway in Rochester, a section of defensive ditch and the underground tunnels system, it originally consisted of a brick keep with an extensive tunnel system incorporating magazines and stores, there were also two guard towers and a defensive arched gatehouse at Borstal Road with a wooden swing bridge across the ditch. The towers, situated at Maidstone Road and beside the River Medway, were connected to the main keep by a length of fortified ditch with ramparts, the fortifications were built to protect Rochester from a landward attack and also from a river bound attack. In 1808 twenty-three acres of land, one rod, and thirteen poles were requisitioned by The Crown under the Defence Land Act from the Dean of Rochester, the Bishop of Rochester and a Mr. W. Head. Works were not completed until 1812 however before this time Military Tacticians already considered them obsolete. Armament at the Fort Clarence main tower and flanking casemates were listed as 12 x 12pounder cannon and 6 x 18pounder carronades, however a month later it was recorded that four thousand and five hundred barrels of gunpowder were to be removed due to the Medical Department taking the site over. Storehouses close to the tower were converted into accommodation for the medical staff and the main tower was used as a Naval Lunatic Asylum and hospital with a small amount of land nearby used as a military cemetery.
In 1845 the fort ceased to be used as a hospital and over the following year it was adapted into a military prison, more building were added to the site including a house for the governor, accommodation for the warders and a cell block with an unconsecrated chapel added in 1849. The keep was able to hold twenty two prisoners in 1858 and an additional eighty four in additional accommodation. More prisoners could be accommodated in 1867 with Tyler's Directory stating one hundred and fifty could be housed with room for another fifty convicts. Staff were listed this year as a Governor, an Officer in Medical Charge, a Chaplain, a Schoolmaster, a Chief Warder, seventeen Warders, an Infirmary Warder, a Clerk and a Gatekeeper. Twelve years later there were only twenty two prisoners on site, the Governor, five Warders and three other staff members. 1924 saw the arch that crossed Borstal Road and its associated guard house demolished, there was a lot of publicity as many people wanted them to be saved however the road needed to be widened. The rubble from the archway and guard house was used to fill that portion of the ditch so the bridge could be removed. Around ten years later Fort Clarence was taken over by 166 City of Rochester Battery Royal Artillery T. A, they remained here until the outbreak of WWII. In 1940 the fort was taken over by 33 Battalion (Shorts Brothers) Kent Home Guard, they remained at the fort until the Home Guard were disbanded in 1944. Several alterations were made under the Home Guard, a prison block was adapted into an ammunition store and the chapel was converted to a gymnasium.
Fort Clarence House remained in Army hands until 1974 however the fort was sold to the Post Office at an earlier date. The Post Office bought Clarence House in 1974 and applied the following year to demolish it, the application was denied due to the house being a scheduled monument although the Maidstone Road tower, a prison block and the chapel were demolished. The sally port in the defensive ditch can still be seen, this was used to transport ammunition and stores from the river into the fort via underground tunnels out of sight of the enemy, the tower has now been converted into apartments that cost around ?500,000 each. The ground floor flat has a games room in the lowest level that would have given access to the tunnel system but the tunnels have been sealed. Fort Clarence is a Scheduled Ancient Monument.
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