The Royal Navy ordnance depot at Upnor can be seen on aerial photographs taken during the 1940s and 1950s. This site was situated on the bank of the Medway immediately to the north of Upnor castle. This area had been used as an ordnance store from 1668 when Upnor castle (see NMR 416743) was converted into a magazine to serve the Royal Navy. The mid-20th century air photos show the result of a gradual expansion of this ordnance site northwards along the bank of the Medway. The depot closed in the 1960s since when a number of buildings have been demolished. This site has been mapped from 1950 air photos as part of the English Heritage: Hoo Peninsula Landscape Project.

By the late 18th century Upnor castle's storage capacity was proving to be insufficient. At the start of the 19th century work commenced on a purpose built magazine (with a capacity of 10,000 barrels) at TQ 7588 7072 and a building in which to examine powder, called as shifting House. These were built to the north of the castle and completed by 1812. Capacity at Upnor was again deemed insufficient by the mid-19th century and shell stores and another magazine with a capacity of 20,000 barrels were built (at TQ 7589 7077). Additional buildings were constructed to the north and west of these magazines during the later 19th and early 20th centuries. These included filled shell and mine stores as well as buildings to undertake a variety of processes such as shell filling. Ships were loaded and unloaded via a large and elaborate pier, since demolished, which was joined to the shore at five separate points. By the late 19th century additional ordnance storage was provided by the new depots circa 2km to the north at Chattenden (NMR 1481790) and Lodge Hill (NMR 1077634), both of which were connected to Upnor by railway.

Aerial photographs taken in 1950 show a number of buildings including air raid shelters built during the Second World War. The earth covered shelters were built on the higher ground west of the 1850s magazine (at TQ 7585 7084, TQ 7582 7081 and TQ 7582 7064). Two wartime buildings were also within this area at TQ 7583 7081 and TQ 7579 7070. Wartime buildings were also constructed immediately behind the 19th century magazines and a single building near the most northerly access to the pier at TQ 7596 7090. All of these have been demolished. Surviving buildings include the 1850s magazine (TQ 7589 7077), a group of buildings centred on TQ 7593 7088 - which include what were originally shell stores and a wet guncotton store - and the large filled shell store at TQ 7598 7097. One of the surviving shell stores at TQ 7593 7086 was given a flat roof during the war.(1-4)

Archive: MD003093 Hoo Peninsula Landscape Project: TQ 77 S E Material still held by Aerial Survey.

<1> Canterbury Archaeological Trust, 2006, An Archaeological evaluation at the R.S.M.E. Engineering Park, Lower Upnor, Medway, Kent (Unpublished document). SKE32452.

<2> David Evans, 01/01/06, Arming the Fleet (Article in monograph). SKE14478.

<3> RAF, 1950, RAF 58/482 5142-5143 5-JUN-1950 (Photograph). SKE55983.

<4> Next Perspectives, 2007, Next Perspectives PGA Tile Ref: TQ7570 21-APR-2007 (Photograph). SKE55984.