The ‘zero’ stations were covert radio relay facilities, buried underground and designed to transmit information secretly in the event of a successful German invasion.
A total of 32 were built, but such is the level of secrecy around their construction (and maintained by thoe who staffed them) that only 12 have been found.
The Wakehurst station is though to have linked to Army HQ in Sevenoaks and was staffed by women from the Auxilliary Territorial Service. By 1944 the threat of invasion had lessened significantly and the site was decommissioned and sealed up soon after.
It is not possible to view the interior. Now all you can see is a few white posts which mark the ventilation tubes and a bit of wire up the tree.
A detailed archaeologcal survey was commissioned by the National Trust in 2009-12.
