Written by Nick Catford on 01 May 1995.
Originally constructed as an Anti Aircraft Command operations room in 1951, and disused in 1960. It formed part of the Pendell Army Camp which was removed to make way for the M23.
The bunker is situated adjacent to the London-bound carriageway of the M23 at junction 8 at the bottom of an embankment. The radio array can be seen from the motorway.
The site was taken over by the Home Office in the early 1960s and allocated to the Metropolitan Police as its southern war headquarters, and remained so until 1991, when it was partially stripped out. Some equipment was still in place when visited by Sub Brit members in 1995.
The bunker was sold in Autumn 2001 but nothing was done on the site and it was used for grazing gypsy horses. The bunker has now been sold again and ongoing work is now taking place.
A similar bunker is situated at the Metropolitan Police training centre at Lippetshill, Essex, which was intended for controlling the northern part of London in wartime.
Written by Neil Iosson on 13 November 2021.
Merstham AAOR has now, sadly, been long abandoned. It is in a poor state with partial flooding of approximately 1m in the lower floor and extensive deterioration and rotting of wooden floors and partition walls.
The site has been privately owned for a number of years and has a fence partially surrounding it. The main entrance has been adapted with block walls at either end of the outer porch (and a door at one end) to create an additional room. This room has been subject to a fire and a wall partially demolished - permitting access into the building.
The building follows a fairly typical AAOR pattern with an upper floor and lower floor surrounding a double height central operations well. There are two main sets of stairs connecting the floors and two additional sets in the far corners.
The lower floor is flooded to about 1m depth with unpleasant, polluted water and is inaccessible. Unfortunately the damp has encouraged rapid deterioration of fibreboard partition walls.
The outer circle of rooms making the upper level have a concrete floor (with partially deteriorating tiles. The flooring of the upper level of central well is a suspended wooden floor and is clearly rotten and missing in places, with a view to the dank liquid below. The entire floor within the central operations room should be considered unsound and very dangerous and not walked on
The northern and southern main rooms of the outer ring show evidence of being originally subdivided into two smaller rooms each - with a dog leg corridor passing between them - but these have been deliberately demolished and removed at some point to make much larger spaces. Both of these rooms have considerable debris and some graffiti.
There is a large male toilet area in the north east corner and a smaller female toilet, complete with sanitary towel incinerator, in the south west corner. Both have been badly vandalised. There is also a small kitchen area next to the female toilets. Most of the other rooms have no clearly discernable purpose.
Oddly, both toilet blocks have 12in diameter extractor fans which vent via a louvred grate to the outside. There appears to be no system of filtration or anything to prevent radioactive fallout from entering via these routes.
The only evidence of major plant visible is a large block and tackle above the stairs by the main entrance and a large air vent coming up from the lower floor.
In the far north west and north east corners are secondary staircases to the lower level. Above each of these is a small (water?) tank, which is accessed by a fold-down stairs going up stored in the ceiling above the permanent descending stairs. It seems an unusual arrangement.
The observation cabins looking down to the lower floor of the operations well are in remarkably good condition with much of the plexiglass in place. Wooden desks and drawers are also well preserved.
At least one of the causes of water ingress is due to leaks in the roof from plants working their way through the waterproof felt and concrete and in many places thin roots hang from the ceiling gently dripping water into the building.
Most doors are still in place and painted although there is very little signage relating to its use at any stage of its life.
The adjacent parking area is inaccessible by vehicle due to obstructions placed in the access road. It has a substantial collection of old skips and some other rubbish. The site can be easily seen from the public footpath that runs alongside.
