Former A (No. 1) Magazine And Enclosure Walls, 100M N Of Marchwood Yacht Club Offices

Former A (No. 1) Magazine and Enclosure Walls, Marchwood

This brick-built magazine was constructed between 1814 and 1816 at the Royal Naval Armaments Depot in Marchwood, Hampshire. It was designed according to plans prepared by Lieutenant-General Sir William Congreve, Baronet, Colonel Commandant of the Royal Artillery and Controller of the Royal Laboratory at Woolwich. The building originally had a roof of pantile and slate.

The magazine consists of a simple rectangular structure set within an outer enclosure formed by red brick walls. The enclosure has a gateway to its south, flanked by square piers each bearing a round-headed recessed panel surmounted by a slightly projecting square panel. The corresponding entrance on the north side is incorporated into the Receiving Room building.

The magazine originally featured a triple-pitched roof with prominent lightning conductors. It has three windows at each end, each with a small stone ledge beneath it. Additional small ventilation openings are set within Portland stone surrounds, originally fitted with wooden doors. These ventilation openings complemented voids built into the brickwork to facilitate air circulation and prevent damp. The interior fittings, which would have consisted of rows of racking for storing powder barrels and copper fittings, are no longer present.

The threat of French invasion in 1779 and the Napoleonic Wars prompted a fundamental reform in British gunpowder storage and distribution. Previously, powder had been kept in bombproof structures within old fortifications or massive vaulted buildings. Two national centres of powder production existed at Waltham Abbey and Faversham, both established in the 17th century and acquired by the Crown in the 18th century. Under the new system, powder was distributed from eight depots around the country: Purfleet, Tilbury, Gravesend, Upnor Castle, Priddy's Hard and Tipner Point (both in Portsmouth Harbour), Keyham Point at Devonport, and Picket Field in Berkshire. Additional supplies were stored in a magazine in Hyde Park for London and in floating magazines on the River Medway, at Portsmouth, and at Plymouth.

In 1811, the decision was made to increase the number of depots and replace floating magazines with permanent storage facilities. Four new magazines were consequently built at Dorchester, Carmarthen, North Hyde, and Marchwood. Marchwood became the largest of these four and remained in service longest.

Each gunpowder barrel held 90 pounds of powder. The Marchwood site was designed to store 20,000 barrels. Initially conceived as a single enormous magazine, by 1807 the Board of Ordnance recognised the importance of separate buildings for examining powder and other functions. After extensive deliberation, a decision was made to construct three magazines, placed as far apart as possible, each with a capacity of 6,800 barrels. The design incorporated Congreve's revolutionary soft-top roof concept, which allowed accidental blasts to travel upwards rather than outwards due to low roof resistance. It also employed hollow wall construction to reduce damp penetration, a method patented by John Groves in 1809. A canal for moving barrels by barge between magazines was built south of the structures. This small canal is believed to be unique; although canal communication was used in major Ordnance factories, this application is considered exceptional. Powder from Marchwood supplied the smaller Portsmouth magazines at Priddy's Hard and Tipner Point and also the fleet off Spithead.

The three original magazines, ancillary buildings, and perimeter wall were completed between 1814 and 1816. Magazine A (No. 1) is the sole survivor of these three original magazines. Magazines D (No. 2) and G (No. 3) were destroyed in 1940.

Four additional magazines were added in 1856 and 1857 following deficiencies revealed by the Crimean War. This second phase of development increased storage capacity to three magazines of 14,400 barrels and one of 9,600 barrels. By 1864, according to The Times, Marchwood had become the largest magazine in the country, with a capacity of 76,000 barrels. The canal was by then superseded by a roller way. The Board of Ordnance was abolished in 1856, and the War Office assumed its responsibilities. In 1890, control of Marchwood passed to the Navy. The establishment began to decline shortly afterwards, with numerous magazines destroyed by bombing in 1940. The Depot closed in 1961.

Despite the loss of some elements, Magazine A retains the important features that identify it as a significant landmark in magazine construction. It dates from a period marking a new approach to gunpowder storage concepts, with no similar listed examples elsewhere. It possesses strong group value with the other surviving buildings at the Marchwood Depot.