Built on the ruins of Haselworth Castle to protect Portsmouth Harbour at the start of the American War of Independence, it was rebuilt in the 1880s as a Palmerston fort.

[2] Despite several previous plans which noted the exposed nature of Portsmouth harbour to attack, it was not until the American War of Independence that construction of a defensive fort was started on the site in 1779.

[3] The Governor of Portsmouth Lt. General Sir Robert Monckton told his Commanding Engineer, Lt. Col. John Archer to draw up plans for the defence of Stokes Bay.

In 1779 the Gilkicker Sea Mark was demolished to provide clear ground for a new temporary fort, which consisted of a 6 feet (1.8 m) thick earth bank, supported by brushwood fascines.

So poor was the structure that the tents of the billeted soldiers blew away in 1780, while the site was so exposed that it was used as a sighting point by ships entering Portsmouth harbour.

However, using civilian and often supplemented by conscript labour, construction speed was slow and the design came under criticism from Charles Lennox, 3rd Duke of Richmond, who in 1782 was appointed as Master-General of the Ordnance.

In 1879, torpedo experiments were carried out at Stokes Bay and part of this consisted of a mock attack on Fort Monckton.

Virtually abandoned after World War II, the fort was however retained by the Ministry of Defence[10] and remained armed until the abolition of coastal artillery in 1956.

[10] Located next to the Stokes Bay Golf Course, much of the original fort still exists including the bastions, sea facing casemates, guard room, one of the caponiers and the ditch.

The fort retains its original drawbridge and is additionally protected by modern razor wire security fencing, CCTV cameras and high intensity lighting.

The site has been heavily modified with modern offices and accommodation added on and around it, and a portion of the artificial lake was filled in during the 1970s.