Land attack

The lines defending Chatham from land attack were strengthened by additions to Fort Amherst and by the construction of Fort Clarence. The greatest weakness of Dover was vulnerability to land attack. The ancient castle - despite being greatly strengthened during the 1790s - was also vulnerable to attack from land, especially from the neighbouring Western Heights from which modern artillery could rapidly reduce the castle to ruins.

The answer hit upon by the military was to transform the Western Heights from the weak link in Dover's defence into its greatest strength. From 1804 until 1814 was turned into one of the great artillery fortresses of Europe. It housed batteries firing out to sea and inland, and barracks for a large garrison of troops that was given rapid access to the sea by means of the spectacular Great Shaft, a 140 foot deep cylinder containing three staircase designed to allow troops to move to and from the Western Heights and the harbour with maximum speed. The Western Heights was also provided with an impressive strong point - a place of great defensive and offensive power - called the Drop Redoubt. This fortress with its massive, brick-clad earth walls, deep ditch, well sited gun embrasures and vastly strong casemates and magazine remains one of the wonders of British post-medieval military design.

The greatest weakness of Dover was vulnerability to land attack.

The defence of the Romney Marches was a trickier problem. Flooding was one possibility but this would have destroyed many homes and much productive land. In late 1804 a Royal Engineer colonel John Brown came up with a better idea: dig a 62-foot wide canal along the north edge of the march; keep its water level high with the use of sluices; and build a military road and rampart along its north bank so that it would function as a defended moat in case of French attack. The idea was approved immediately by Prime Minister William Pitt and the Royal Military Canal was completed by 1809. Its construction was a colossally expensive exercise - £234,310 - and was subsequently much mocked as an act of absurd military folly. William Cobbett's reaction in 1823, in his Rural Rides, was typical; 'Here is a canal... made for the length of thirty miles... to keep out the French: for those armies that had so often crossed the Rhine and the Danube were to be kept back by a canal.' Cobbett had a point but he missed the main one: the canal was only a part of a co-ordinated system of defence intended to wrong-foot the French invader, not to stop him.