Fan Bay Deep Shelter

The tunnels lie 23 metres down in the cliff and were dug by Royal Engineers between November 1940 and February 1941 for the gun battery's crew.

The National Trust rediscovered them in 2012 and, after about 18 months of work that included clearing 100 tonnes of rubble, opened them to the public on 20 July 2015.

The guided tour in hard hats and head torches takes in two First World War sound mirrors, early-warning devices that focused the noise of aircraft engines.