Chapter One : Construction and function as a Napoleonic Fort

The origin, of what became known as Fort Clarence, began in the 18th Century when the idea of a fortification on St Margaret’s Heights in the city of Rochester emerged as part of a wider scheme to extend the land defences of Chatham Dockyard. This was reflected in an inspection by the Senior Committee of Engineers in 1783, when Colonel Debbieg of the Royal Engineers drew up an idealised sketch plan for new defences which included a small work on St Margaret’s Heights, to the west of the Dockyard, in Rochester. The outbreak of war with France in 1793 underlined the need to extend the defences, but it was only the imminent threat of invasion which jolted the Government into action and precipitated new works. 

In 1803 Britain had declared war on France, led by its military genius of an Emperor, Napoleon Buonaparte and would remain at war with France for over a decade. His invasion plans of Britain had a significant impact on British naval strategy and the fortification of the South East England coast and the fortifications built in the Medway Towns were a major part of that strategy. Against this background, Fort Clarence, was built in 1808, three years after the construction of the neighbouring Fort Pitt started, with the intention that it would guard Rochester Bridge and thwart any attempt by a French army landing in Kent and crossing the River Medway and then marching along Watling Street to London. 

The Fort was almost certainly named after Prince William, the forty-three year old, third son of King George III, who had been given the title of the Duke of Clarence and St Andrews. The Fort Clarence built in Halifax, Canada to counter the French enemy there, at the same time, was named the Duke of Clarence’s Tower. (link) After a career in the Royal Navy, the Duke had risen to the rank of admiral and despite repeated petitions he wasn't given a command during the Napoleonic Wars. In 1830 he ascended the throne and King William IV.      

Under the Defence Land Act, compulsory purchase of over 23 acres of land were requisitioned for construction of fortifications, by the Government, in the name of the Crown. The land in question was owned by the Dean of Rochester, the Bishop of Rochester and a Mr W. Head. Over the next four years work proceeded slowly. Unlike its sister fort, Fort Pitt, it was not concentrated on one site but stretched out on two arms, from the Rochester Maidstone Road at its east end to the banks of the River Medway in the west. It had a large tower at its centre and two smaller towers at each end of its 250 metre long, defensive ditch. The officer in charge of the whole project was Lt Col D’Arcy of the Royal Engineers. The layout of the Fort is Illustrated below and with thanks to Keith Gulvin, with D'Arcy's original plan for the central Tower, here on the right. 

It was basically a strongly fortified ditch and rampart or embankment, with magazines, the  rooms to store gun powder and ammunition, built underground. It was specifically constructed to defend Rochester and its bridge across the Medway from a French land attack but also to prevent a river-borne landing along the eastern bank of the River Medway the Fort defended. In the overall plan of the defence of the Bridge and Chatham Dockyard from French attack, Clarence was at the western end of the defensive line consisting of Delce Tower, the mighty Fort Pitt and Gibraltar Tower. They connected to the formidable defences in the east, centred around Fort Amherst which towered over the Dockyard.

At the intersection of the Fort and the Borstal Road, a wooden swing bridge was built to carry the road across the ditch and a large brick work archway and block house were built to defend against an enemy approach from the south. What became known as Clarence Tower can be seen to the left of the archway with the photograph taken from the inside of the fortifications looking south. Here it is today, with its modernised roof area as part of its conversion into modern private accommodation and, on the right, reimagined by Keith Gulvin, as it was as a functioning fort when completed in 1812. A large area to the rear of Clarence Tower, i.e. to the north of the Tower, was walled in and probably served for parade and drill area. 

From the roof of the Tower, the strength of its position can be appreciated, with its view along the Medway to Rochester Bridge to the north. In addition, it also had a clear view of the other Napoleonic defences to the east in Rochester and Chatham.

In the event of an attack the Fort was supplied by a sally-port, its secure entryway, in the ditch above the Medway Tower. Brought in by boat on the River stores and munitions could be unloaded in relative safety and transported through underground tunnels to other parts of the Fort. Clarence Central tower was at the heart of the fortifications and had tunnels connecting it to other parts of the Fort, many of which  still exist. (link) The one leading down to the River Medway terminated in casemated gunrooms known as the West Casemates.

The whole fort was garrisoned and armed only for a short time when the Napoleonic threat was at its highest. Its firepower consisted of fourteen 12-pounder cannon, twelve 18-pounder carronades and six 12-pounder carronades recorded in the inventory made in January 1819. By this time with the Napoleonic threat gone, it was recorded that a total of 4,500 barrels of gunpowder were removed from the Fort. Apparently, as a Fort, it was considered obsolete, as far as military tacticians were concerned, even before its building was completed. 

In 1820, redundant as a working fort, Clarence, still under Army control, now took on a new role as a home for : 'Unfortunate persons belonging to the Army who were afflicted with insanity' and in June began to provide care for a number soldiers with mental afflictions referred to it from its sister fort, now the Fort Pitt Army Hospital in neighbouring Chatham.

For more information the English Heritage report of Fort Clarence published in 2002 and written by Paul Patisson provides the professional survey of the site. (link) In his opinion this surviving part of the military history of the Medway Towns with its a military line on the land front allied to a surviving fortified tower, was a defensive arrangement regarded as :  ‘rare, if not unusual for its time’.

John Cooper

Chapter Two : The Fort becomes a hospital and then an Army prison 

Chapter Three : Fort Clarence in the 20th and 21st centuries