A new fort to defend the port of Newhaven was a recommendation of the 1859 Royal Commission on the Defence of the United Kingdom, during the administration of Lord Palmerston.

[1] A 40 foot wide moat protected the northern and western sides of the fort, which were lined with concrete, the first time this material had been used to any extent in a British fortification.

[1] The fort proper was originally armed on the eastern side in the 1870s with two 9-inch rifled muzzle-loading guns on Moncrieff disappearing carriages, the only such arrangement in the UK.

Restoration began in 1982 following a failed commercial redevelopment venture, and 6-inch Mk VII guns have been re-installed in the fort to approximate the 1906 - 1941 armament.

In the BBC TV programme Great British Railway Journeys (Series 7, Episode 7), Michael Portillo visited Newhaven Fort.