A set of tunnels, known as the Esplanade Level Tunnels, are located close to street level at the foot of the cliff face. These were originally excavated in the C19th buy were substantially extended in the C20th. In 1938-9 Dover Council began to extend this network of caves to provide civilian air raid shelters which by 1943 could accommodate 1000 people.

The tunnels extend a considerable distance east-to-west and beyond the footprint of Dover Castle. There is a long, straight east-to-west tunnel: the Guildford Tunnel (c.600 - 700 m long) with c.4 branches to provide access from the cliffs. At the west end is a network called Trevannion tunnels around one entrance while at the east end is another smaller network around Athol Terrace. Another section of the network is Chapel Cave which remains in private ownership and which is where John Smith excavated the original cave for his burial place. Summarised from sources (1-2)

<1> English Heritage, 2014, Dover Castle Conservation Management Plan Volume 2 Gazetteer (Unpublished document). SKE52105.

<2> Johnathan Coad, 1995, English Heritage Book of Dover Castle and the Defences of Dover (Monograph). SKE52106.