Fort Amherst

Coordinates: 51°23′14″N 0°31′33″E / 51.38730°N 0.52570°E / 51.38730; 0.52570 Fort Amherst, in Medway, South East England, was constructed in 1756 at the southern end of the Brompton lines of defence to protect the southeastern approaches to Chatham Dockyard and the River Medway against a French invasion. Fort Amherst is now open as a visitor attraction throughout the year, running tours through the tunnel complex.

The primary purpose of all the Medway fortifications was the defence of the Naval Dockyard.

Land was acquired by two Acts of Parliament in 1708 and 1709. The land was surveyed in 1715 by the Duke of Marlborough. The first plan of defences was an enceinte, from Gun Wharf, Chatham, to north of the village of Brompton. It was designed by Capt. John Desmoretze in 1755 and consisted of a 9m wide ditch and a 3m parapet. The strongpoint of the design was the Amherst Redoubt which became Fort Amherst. It was completed in 1758 and defended with 14 42-pounders, 10 9-pounders, 8 6-pounders and 2 4-pounder guns. These became known as the Cumberland lines, and were entered by four gateways with bridges.

In 1770 Lt General Skinner extended and strengthened the lines, the Amherst Redoubt was strengthened, further batteries added (such as the Cornwallis Battery) and the ditches revetted (lined with brick).

During the Napoleonic Wars the Chatham defences were enlarged and strengthened considerably. In 1802-11 prisoners were set to work on extending the tunnels and creating vast underground stores and shelters, new magazines, barracks, gun batteries and guardrooms. More than 50 smooth-bore cannon were also mounted. The last building works were about 1820.

A maze of tunnels dug into the chalk cliffs were used to move ammunition around the fort.

A second gun battery, Townsend Redoubt, was built at the northeastern corner of the dockyard at the same time as Fort Amherst. Both forts were inside the 1756 brick-lined earthwork bastions known as the Cumberland Lines, which surrounded the whole east side of the dockyard down to St Mary's Island. These have now been built over.

Fort Clarence in Rochester and Fort Pitt, on the Rochester-Chatham borders, were built in 1805-15 to protect the southern approaches.

Fort Amherst has been described by English Heritage as the most complete Napoleonic fortification in Britain and as such has great national historical significance.

The fort was still in use during the Second World War and restoration to make more areas open to the public is in progress.