The tunnels are lined with corrugated steel arching and the complex originally included five large tunnels with storage space for bunk beds, rifles, a hospital and a secure store, a generator, toilets and washrooms. The gun battery was intended to attack enemy shipping moving through the English Channel.
The tunnels were abandoned in the 1950s and filled in with debris in the 1970s. In 2012 the tunnels were rediscovered by the National Trust after purchasing this section of the cliffs. The restoration work, carried over 18 months, included removal of 100 tonnes of rubble.[5] The tunnels were opened to the public on 20 July 2015.