Power came from three power stations, one of which was within what was now called the radar garden, within the site perimeter. The other two were at remote locations, each about two miles distant, and connected by ring main to a substation at the inner end of the sloping entrance corridor to the bunker. These power stations were equipped with heavy MAN diesel engines direct-coupled to large alternators. The previous 24 hour mobility standing order to which 537 SU had to adhere could clearly no longer apply. It was therefore for the potential destruction of these generators, and the denial of other equipment in the event of invasion, that I had been instructed in demolition, and held a stock of plastic explosive and detonators in the Armoury.
Outside the main gate was a turning area for vehicles where the lane had been widened. Entrance to the site was via a Guardroom housed in an innocuous German-looking building situated almost at the roadside. All personnel had to prove their identity to the SPs on duty before entering this building. Access to the bunker was from the back of, but within, the Guardroom, down several flights of stairs leading to the sloping entrance corridor. In this corridor were shoe racks where all personnel, except SNCOs and Officers, took off their outside footwear and changed into plimsolls. Also in this area was a vertical ladder rising to a surface manhole atop a narrow shaft where cabling rose to the surface. Beyond were several dog-leg, blast protection, turns to negotiate before entering through heavy steel blast doors into the corridor running the length of the upper floor of the bunker proper. At each end of this corridor was a stair well leading to the lower floor. At the far end of this same corridor was another set of blast doors, through which were two enormous air intake fans drawing fresh air down a vertical 20 feet square shaft, which also served as an emergency escape route. This shaft ended in a louvered building on the surface. Exhaust air left the bunker via the usual access tunnel (this gave it a smell not dissimilar to that of a London Underground station). The square ventilating shaft had, rising within it, a series of iron stairs and platforms which gave access to security doors at the surface. These had to be checked during the night watch when the Duty Watch Officer had the opportunity. Whenever it was my turn, it was a blessed relief to go up this shaft on an early summer morning and briefly see the sun rise. On one such occasion someone down below extinguished the lights and I had to grope my way down in the blackness and past the fans, where there were several awkward concrete steps, to find the handles of the blast doors so that I could get back into the bunker. It was my duty, also, to climb the narrow cable-shaft ladder to ensure that the ground-level manhole was still properly secured.
The bunker could be sealed, and the air conditioned and recirculated in the event of a chemical or biological threat or attack. The plant rooms capable of doing this were along the right side of the corridor, as well as toilets, crew rest rooms, a small canteen/kitchen, and an emergency lighting accumulator room. On the other side of this upper corridor were the C & R surveillance room, control cabins, training room, Chief Controller's cabin, and other necessary offices.
The lower floor had a similar corridor but, in my time, many of the facilities available (air raid warning, civil defence, Army liaison, Ack-Ack control, and other communications facilities) were not used, even under exercise conditions. Those that were in regular use were, the GPO/Deutsche Telefon equipment room, the radar office, the radar workshop, and store rooms.4 Most important though, with access from this floor, was the Operations well.
The well extended the full height of the bunker and was surrounded on most of three sides by the windows of the various command cabins. The Chief Controller's
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4 The GPO = General Post Office (telephones) wired the bunker under contract, but the German telephone service provided all the land-lines. The radar office was where the radar signals were processed for distribution to the PPIs and other equipments throughout the bunker. The radar workshop was part of this facility.
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