Site Name: Landguard - Interim AAOR for Harwich GDA
Sub Brit site visit 5th February 2005
[Source: Nick Catford]
In 1950 a rapid expansion in ant-aircraft defences was implemented with a plan to build purpose built AAOR's covering all the GDA's with a number of new and eventually automated gun sites.
The AAOR was not located in the fort itself but in 'Left Battery' one of the outlying Victorian gun batteries located close to the fort. Coastal artillery was already controlled from a plotting room inside the fort.
Photo:Landguard AAOR built within a Victorian 10-inch RBL Moncrief gun emplacement
Photo by Nick Catford
The Left Battery dates from the 1891 and consisted of three gun emplacements housing two 6-inch and one 10- inch guns set within a substantial earthwork. The 10-inch RBL utilised a Hydro-Pneumatic disappearing mount (similar to a Moncrieff) which required a very deep emplacement allowing the gun to be retracted below the top of the emplacement. The Hydro-Pneumatic emplacement was selected at the location for the AAOR. It was roofed over with a brick extension to the rear forming the front of the new building.
Inside two large rooms were provided one was the plotting room and the other the GPO frame room. These were access from a short corridor along the front of the building. The operations room had a circular plotting table in the centre of the room with a raised dais around two sides with four plotting positions overlooking the table. Each position had a 20 line keyboard set into the desk. From one of these positions the controller could view the activity on the plotting table and give orders to the gun sites in his sector.
The GPO room next door had a bank of batteries against the back wall
with a battery charger and the Main Distribution Frame against the partition
wall. A GPO apparatus rack stood in the middle of the room containing
signaling units, keyboard speech circuits and telephone jack speech
Layout of the Landguard AAOR
Drawn by Nick Catford - Room layout added from memory by Tom Barrett who installed the equipment
During the 1950's the three emplacements of Left Battery were backfilled and earth was banked up at the rear. All that was visible were the aprons for the 6-inch emplacements and the roofed over 10-inch (the AAOR). Left Battery remained in this state until September 2000 when English Heritage began an archaeological dig, exposing the emplacements and their rears.
Once the earth was removed it was possible to enter the AAOR where a black painted board showed the layout of the Harwich and Felixstowe area anti aircraft guns was found. Each site was marked on this board and had indicator lamps which shoed if it was manned and/or firing. An anti gas door frame was also found in situ in the entrance passage.
The internal structure of the Hydro-Pneumatic emplacement could clearly
still be seen with the internal curvature and overhand visible in both
rooms and three ammunition recesses visible in a fourth room, accessed
from the plotting room at the back of the AAOR. Inside the building
was very wet and most of the woodwork rotten and beyond repair. Originally
the walls were studded and covered in hardboard but most of this was
found on the floor in a mushy state. With the exception of lighting
fittings most of the electrical fittings, isolation switched and fuse
boxes have survived on a panel in the plotting room.
Photo:The plotting room - the curvature of the old gun emplacement can clearly be seen
Photo by Nick Catford
The wooden plan of the surrounding gun sites has now been removed for safe keeping and restoration and there are plans to restore the AAOR at some time in the future and open it to the public but for now the building is without power and although much of the rubbish has been cleared away the rooms are still damp. The whole site is surrounded by a secure palisade fence.
The AAOR and its later replacement at Mistley controlled six heavy anti-aircraft batteries. Only one was emplaced with guns, the others being designated pre-surveyed sites. On declaration of an emergency mobile 3.7" guns would have been moved in along with Nissen huts for a control room and ammunition magazine; GPO and electricity cables were already in place.
The only fully fitted site was at Trimley Heath (HW2) at OS Grid Ref: TM275360 which was built between 1948 - 1950 and emplaced with four 5.25" guns. Today the site is virtually complete with control room, gun store, generator house, radar platform and the four gun pits three of which are filled in with rubbish.
The other five emplacements in the Harwich GDA were Royal Hospital (HW44) at TM161353, Shotley Street (HW44) at TM237345, Wix Abbey (HW46) at TM168292, Foulton Hall (HW47) at TM232285 and Walton Hall (HW48) at TM263243. These were all mobile sites and they have left no visible remains. When Mistley opened in 1953 the six sites were redesignated with a 6 prefix. E.g. HW45 became HW645.
All the sites were abandoned in 1956 on the abolition of Anti Aircraft Command.
Click on thumbnail to enlarge
[Source: Nick Catford]
Last updated 9th October 2005
© 2005 Subterranea Britannica