Portsdown Main
Portsdown Main is a prominent feature on the Portsmouth Landscape, it is a huge art Deco building designed in the 1930’s but actually built in 1952 as the war interrupted its construction.
It original use was as an Admiralty Research Establishment. It saw many changes over its years in use and 
was also used as the Admiralty Surface Weapons Establishment and the Defence Evaluation Research Agency.
The site of Portsdown Main is approximately 46 acres and is sandwiched between Fort Southwick and the Marine Warfare Centre.
Portsdown Main closed its doors in January 1997 and a lot of documents found on notice boards still date from late 1996. The canteen/restaurant building still has Christmas decorations in the bar area!
The machinery buildings are vast, cranes and non moveable machinery are still in place. This part of the site was apparently used for testing heavy marine equipment.
The electric in the Main Art Deco building was still on in part of the tunnels, which made us all a little nervy. The staircase is typically Art Deco and very impressive. Upstairs most of the rooms are bare with just some 
signs on the doors giving an indication of the important decisions made within.
The canteen bar area has a definite late 1970’s retro feel to it with groovy light fittings, but the staircase again is ornate and impressive.
Now it is no longer a live MOD site there are plans to sell it as a mixed used devolvement.