Built in 1941 under a series of tunnels dug during the Napoleonic Wars. The Napoleonic tunnels were put into service by Admiral Ramsey to command Operation Dynamo. The 1941 tunnels are known as Dumpy.
A mirror of Dumpy was constructed just below the Napoleonic tunnels but was abandoned owing to a fault in the chalk.
Dumpy served as a joint service headquarters. At its heart was a two-storey galleried operations room used to control operations of all three services in the northern channel area. Dumpy remained in use until the mid 1950s as a fortress, plotting room and NATO communications centre, until the demise of coastal artillery and the building of the NATO Ace High tropospheric scatter communications system.
Dumpy was abandoned until 1962 when the Home Office moved in and took over. The underground works became RSG12. By far the largest of the RSGs, it also spread to the upper levels, taking in the W.W.II dressing station which was built above the Napoleonic works and which became the dormitory area for RSG 12 and later SRC 6.2. The complex was variously placed under care and maintenance and reactivated depending on which government was in power throughout the 60s, 70s and early 80s.
Eventually money and the Soviet SS20 spelled the end of Dover as an SRC. When Dover became an RSG in 1962 the air conditioning to service the complex was rebuilt and switched on. It ran continually throughout its service and is still running. Without it the tunnels would be unusable even in peacetime. Simply heating and keeping the place aerated was extremely expensive. Besides, Dover was now the main reinforcement port for the BAOR and in itself a major target for Soviet SS20s (apparently the target for 1 sea burst and 2 ground bursts of 150kT each). The site was stripped, abandoned and handed over to English Heritage. Operations were transferred to the new RGHQ at Crowborough.
English Heritage intends to reopen the SRC at some point in the future for an ‘anniversary of the Cuban Crisis’ - even though the site was almost certainly not manned during this period. If the restoration is as good as the rest of the tunnel system it will be well worth waiting for.