Military History | Fort Widley, Portsdown Hill — The Powder Magazine's Second War

Historic England's listing describes the fort's core in one clause: an "underground gallery cut through chalk" running from the centre of the barrack block to an underground magazine, and on to a spiral staircase with an ammunition hoist rising to parade level. The chamber was cut to hold black powder. Its history note says only that the work was "part of Palmerston's defences, initiated in anticipation of a war with France", and dates the fort to "c1860", crediting Captain William Crossman of the Royal Engineers. Producers disagree on when it was finished; 1868, 1870 and 1871 all circulate. The French war did not come.

Ninety years later the magazine was taken again. Arthur Corney's 1984 study for Portsmouth City Museums records that in 1953 an emergency civil control centre for the city was built in the fort's magazine; separate research published by Portsdown Tunnels puts the conversion in the magazine and the ground floor of the barrack block. The Treasury file at the National Archives, T 225/299 of 1954, is plainer about what was being paid for: the "Admiralty: contribution towards the conversion of part of Fort Widley, Portsdown as a combined passive defence protected headquarters." Combined, not municipal. The date of its formal opening circulates widely and rests on a single line of research, so it is left out here.

Portsmouth leased the fort in 1961 and bought it outright in 1972. An equestrian centre now works the parade ground.

In April 2026 the charity that runs the site received £40,500 from the National Lottery Heritage Fund for Command & Control, a feasibility study into whether the chamber below can be conserved and shown to visitors at all. It reports in December 2026.

📸 Cover: the fort from the north, the whole polygonal work with Portsmouth and the Solent beyond; the control centre is underground and not visible in any freely licensed photograph. Photograph by Hunanuk, 2 July 2018, CC BY-SA 4.0 via Wikimedia Commons. Second image, the barrack and stores range along Portsdown Hill Road; by ITookSomePhotos, 20 July 2021, CC BY-SA 4.0.