Located 23 metres underground, Fan Bay Deep Shelter was constructed in the 1940s as part of Dover’s connected offensive and defensive gun batteries, designed to prevent German shipping moving freely in the English Channel.


The shelter accommodated and catered for four officers and up to 185 men of other ranks during counter bombardments.

Forgotten after the Second World War, the tunnels are remarkably well preserved. Here, we bring you 12 facts about Fan Bay Deep Shelter, located on the edge of Fan Hole beneath the White Cliffs of Dover…

1) The tunnels were carved out of the chalk cliffs in just 100 days by Royal Engineers from the 172nd Tunnelling Company. Construction of the Fan Bay battery began on 20 November 1940, and the site became fully operational on 28 February 1941.

2) The tunnels were constructed following a visit to Dover by Winston Churchill in July 1940, during which he was enraged to discover enemy shipping moving freely in the English Channel. He sent a memo to the joint chief of staff: “We must insist upon maintaining superior artillery positions on the Dover promontory, no matter what form of attack they are exposed to. We have to fight for command of the Straits by artillery, to destroy the enemy batteries, and fortify our own”.

More like this

3) The Fan Bay gun battery was planned as part of the coastal defence network in the months after the Allied evacuation from Dunkirk – by June 1940 the Dover Strait and the White Cliffs had become Britain’s front line in the Second World War. The battery would ultimately help to close the Channel to enemy shipping and deter invasion.

Art.IWM ART LD 1093

Fan Bay Deep Shelter, the only surviving image of the tunnels. © Imperial War Museum

4) Constructed 23 metres below ground, the shelter had three entrances and was reinforced by heavy duty iron girders and metal sheeting (equipment borrowed from the coal industry), much of which still survives today.

5) The finished Fan Bay battery boasted some of the most cutting-edge technology and weaponry of the time. It had three six-inch guns, each with a range of 14 miles (one specifically sited to give protection to the entrance to Dover harbour); radar; plotting rooms and five large chambers providing bomb-proof accommodation, with space between bunks designated for rifles. The shelter also featured medical facilities and a secure store. Both the deep shelter and gun battery were personally inspected by Winston Churchill in June 1941. Power was supplied from a dedicated generator room, and the tunnels were ventilated by a system of galvanised ducting running along the ceilings, some of which survives today.

6) The tunnels were manned by troops from the 203rd Coast Battery, Royal Artillery: on 10 December 1940, four officers and 118 men of other ranks arrived from Falmouth. This regiment later became the 540th Coast Regiment, Royal Artillery under a unified command with the gun batteries at South Foreland and Wanstone Farm.


Fan Bay Deep Shelter, main tunnel. © National Trust/Larry Stewart

7) The battery site was chosen because it had been in use during the First World War, when sound mirrors were constructed in the upper cliff face. One of the first early warning devices invented in the UK, sound mirrors gave advanced notice of approaching enemy aircraft. The battery site was also located just 21.5 miles from France – geographically the closest point in the UK to France.

8) The shelter is the largest of its kind in Dover and one of the deepest recovered from the period, at 23 metres below the surface. The tunnels are deeper than the nearby South Foreland Lighthouse is high. From today visitors can descend the original 125 steps into more than 3,500 square feet of tunnels.

9) The shelter was decommissioned in the 1950s and filled in during the 1970s. The biggest tunnel in the complex, which is more than 100 feet long, had partially collapsed after vandals had set fire to its wooden supports.


The White Cliffs of Dover, beneath which the Fan Bay Deep Shelter is located. © National Trust/John Miller

10) A large amount of wartime graffiti survives in the tunnels – more than at any other underground site, it is believed. Highlights include coarse inscriptions, rhymes and ditties found close to toilets relating to using the toilet or the lack of toilet paper. One such inscription reads: “If you come into this hall use the paper not this wall. If no paper can be found then run your arse along the ground”.

Graffiti found elsewhere in the tunnels includes names of military personnel; one political inscription – the phrase “Russia bleeds whilst Britain Blancod’s” – and several drawings including a running man and a young man’s face. Games of noughts and crosses have also been carved into the walls.

11) Homemade hanging hooks remain intact inside the tunnels. They were fashioned from a variety of materials – anything soldiers could find. Also discovered was a Unity Pools football coupon dated 20 February 1943, which records 14 football matches; British .303 cartridges alongside American 30 calibre ammunition rounds; and a copy of Shadow on the Quarter Deck – a naval adventure novel by Major W P Drury, published in 1903. The book was discovered on top of an air duct.

12) Fan Bay Deep Shelter is located on land purchased by the National Trust in 2012. The remarkably well-preserved tunnels were discovered during enabling works. Over the course of 18 months more than 50 National Trust volunteers excavated and removed 100 tonnes of spoil from the tunnels by hand.

Facts courtesy of the National Trust


To find out more about visiting Fan Bay Deep Shelter, click here.