Monument MPM1646 - Portals and tunnels to Naval Fuel Bunkers, Portsdown Hill

Tunnels portals belonging to the southern compound of Royal Naval oil reservoirs built under Portsdown Hill in the late 1930s by Sir Robert McAlpine's construction company. The compound consists of two large portals, one belonging to the western pipe tunnel, the other to the eastern service tunnel. Pipelines originally ran from the site to an oil fuel depot at Forton Road Gosport, and holding tanks for the ASWE heating system at Fort Southwick.

A northern compound and valve compound belonging to the oil reservoir complex are located to the north of Portsdown Hill Road at SU623072 and SU622069. The reservoirs were designed to hold emergency supplies of oil for British warships during the Second World War. Furnace fuel oil was held within an underground chamber containing nine storage tanks, each with a capacity of approximately 19,500 tons. The reservoir walls were constructed from 22ft thick concrete in order to make them bombproof. The site also contains a large pre-war pumping station which pumped oil to the fuel jetty in Portsmouth Harbour. The reservoirs were decommissioned during the 1990s.

Hunt, Bob, 2005, Portsdown Tunnels (Bibliographic reference). SPM245.