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Fan Bay Battery - a brief history

Aerial view of two concrete gun emplacements surrounded by grass
Newly excavated Fan Bay emplacements 2 and 3 seen from the air. | © National Trust/Isle Heritage

The genesis of the Coastal Artillery can be traced back to Henry VIII, but as far as Fan Bay is concerned, the story really starts in May 1940. After the end of Operation Dynamo – the Dunkirk Evacuation – both sides saw the need to control the waters of the Dover Strait with heavy artillery. As early as May 1940, Prime Minister Winston Churchill had suggested mounting heavy artillery to counter invasion and strike at enemy shipping, and as the Battle of Britain progressed and possible invasion loomed the need for guns became more apparent.

Churchill Speaks

Angered by lack of progress, on 28 August 1940, Churchill wrote to the Joint Chiefs 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 Strait by artillery, to destroy the enemy batteries and fortify our own.’ These two sentences started the largest and fastest increase in coastal artillery ever seen in the UK. For the first time, artillery would be used as an offensive weapon as well as defensive.

Construction starts

Potential sites for new gun batteries were surveyed and by early September 1940, the locations were finalised. Seven sites were proposed: six at South Foreland, Wanstone Farm, Fan Hole, Hougham, Lydden Spout and Capel-Le-Ferne; the seventh, at Hope Farm near St Margaret’s village, was never constructed.

Priority was given to the sites that could be operational fastest, and in late September, the order was given to start construction of Fan Hole battery. Ground works began in October, with civil engineering company Costain working alongside local contractors and 702 General Construction Company of the Royal Engineers. Work progressed through the very wet and cold winter of 1940/1 ‘in a sea of mud and slush’, but by mid-February 1941, the three guns were in position and underwent proof tests.

The Deep Shelter

To provide protection for the troops from incoming enemy shell fire and aerial attack, a deep shelter was planned with sleeping accommodation 23 metres (75 feet) underground. The shelter was designed to hold 154 men in a series of tunnels, accessed via a 3-flight, 125-step staircase. Two emergency exits would be built alongside the two Fan Hole sound mirrors.

The accommodation tunnels would be lined with heavy grade galvanised corrugated iron, supported by colliery arches – a technique used extensively in the nearby Kent coal mines. Construction started on 20 November 1940, with men from 172 Tunnelling Company, Royal Engineers, mining inwards from alongside the redundant sound mirrors, using hand-held pneumatic rock drills, picks, and shovels. The inland sound mirror was damaged in the process.

203 Coast Battery, Royal Artillery started manning the site in February 1941, having been barracked at the nearby Duke of York’s Royal Military School since December 1940, and the deep shelter was completed by the 28 February. The site was then deemed operational, although construction was far from complete and continued throughout the spring and summer. Later in the year, the Eastern Fire Command would be designated as the 540 Coast Regiment comprising three batteries - South Foreland, Wanstone and Fan Hole, for the rest of the War.

Image of two underground tunnels with bunk beds, bedding and clothing on the beds and a person standing and several seated
Watercolour sketch of life in Fan Bay Deep Shelter depicted by Anthony Gross in May 1941 | © IWM H 27569

The Plotting Room

The Fan Hole plotting room was constructed as a cut-and-cover reinforced concrete bunker approximately 300 metres inland from the three guns. The complex incorporated the plotting room itself, along with a ventilation plant room, two smaller anterooms and the battery command post (BCP). The main entrance was heavily buttressed in concrete, while a much smaller emergency exit shaft was built at the other end of the facility, to reduce the risk of those inside becoming trapped should the main entrance be bombed or shelled.

Targets were identified by the Eastern Fortress Command (Fortress) plotting room (close to South Foreland Lighthouse), augmented by sightings from the observation posts high on the cliffs. Aiming information comprising gun bearing and elevation was calculated at Fortress and transmitted simultaneously to the Fan Hole plotting room and the guns, using a system of electrically linked pointers called 'magslip'. If communication with Fortress was lost, the local plotting room could take over.

The Fan Hole Guns

The three six-inch guns at Fan Hole could fire a projectile – which could either be a high explosive or armour-piercing shell or solid shot – approximately 24,600 yards or 14 miles (22.4 km). An example of a six-inch solid shot, weighing 92 lb (42 kg) is displayed in the deep shelter's seaward accommodation gallery.

All three guns had a clear view of the Dover Strait, and No. 1 gun (the most southerly) could also sight the eastern entrance to Dover Harbour. One of the searchlights at Langdon Bay was connected to the Fan Hole plotting room and could be aimed on command.

During 1942, the smaller coastal batteries were augmented by much larger guns nearby and Fan Hole battery had been renamed ‘Fan Bay’, most likely by the Regimental Commanding Officer Lt Col Richards.

As well as firing live rounds, the Fan Bay guns found another use. German shipping had learned to sail close to the occupied and therefore friendly French coast; out of range of the smaller Fan Bay, Hougham and Lydden batteries. Instead of firing live projectiles, some of these guns were re-deployed as “flashing batteries”. With a full charge of propellant and a solid shot loaded; when the gun was fired, a large flash would issue from the end of the barrel, giving shipping the impression of being fired upon by a larger weapon. This was designed to cause ships to alter course and present a better target to the larger guns, some of which were now using radar ranging.

Black and white image of one of the 6-inch Fan Bay guns with the barrel lowered into the loading position
Fan Bay gun number 2 in the loading position | © National Trust collection

Fan Bay Actions

Although we are often asked how many ships were sunk by the Fan Bay guns, it is difficult to give a precise answer, as the diary kept by 203 Coast Battery has few details. The war diaries for 540 Regiment show the guns being used on at least 17 occasions between 1942 and their last action in September 1944, but in many cases, other guns in the ‘fortress’ were also involved. Altogether the guns belonging to the 540 Regiment fired 3564 shells totalling 3,331,672 lbs and sank 28 ships of various sizes, with many more severely damaged.

The end of the War

By the autumn of 1944, the German coastal batteries had been captured by Canadian troops and allied command of the Strait had been asserted. Aerial bombardment still presented a hazard, now augmented by the fearsome German V1 'doodlebug' and the V2 rocket bombs. Although the Fan Bay battery remained operational, it had ceased firing and this remained the case through to VE (Victory in Europe) Day, 8 May 1945, when Germany unconditionally surrendered and offensive use of the batteries ceased.

Black and white image of a brick gun emplacement with smoke from firing
A Fan Bay gun firing | © National Trust/Victor Smith collection

After the War

With the cessation of hostilities, many of the coastal gun batteries were decommissioned. Those at Fan Bay and Wanstone were kept as coastal training batteries, manned by the 4th Coast Training Regiment, which was formed out of 540 Coast Regiment's permanent staff, on 1st June 1945.

The guns were regularly test-fired until 1950, when the Regiment was moved to Plymouth and all operational equipment was removed from the site. All available scrap metal was reclaimed, and some of the results of this work can be seen in the deep shelter today. By 1957, the Fan Bay site was disused and with Britain still struggling to recover from the costs of rebuilding after the War, the site was prepared for handing back to agriculture. The lower adits to the sound mirrors were bricked up and the metal door at the top of the staircase was secured.

The secret plotting room equipment was smashed into small pieces and removed in the early 1960s. Local historians and eyewitnesses report that the Fan Bay site was guarded by the military police throughout the 1960s. This evidence is corroborated by the absence of grafitti in and around the plotting room and the Fan Bay emplacements. Graffiti and discarded rubbish in the deep shelter tunnels shows that ‘explorers’ were gaining access to the tunnels throughout the 1960s, probably through holes in the bricked up adits, alongside the sound mirrors.

Despite being patrolled, little maintenance was done and the gun sites and deep shelter became a scene of dereliction.

Image of a brick gun emplacement building without the gun taken in the early 1960s before demolition
Fan Bay derelict gun house number 2 taken in the early 1960s | © National Trust/The Ray Harlow collection

‘Operation Eyesore’

In 1970, the Government proposed a clean-up operation to rid cities and beauty spots, such as The White Cliffs of Dover, of the remnants of war. Named ‘Operation Eyesore’, this would give Government grants to local authorities to clear these relics. With local feelings still raw from the intense bombardment that Dover had suffered, Kent County Council successfully applied for a grant. In late 1972 the Fan Bay emplacements, plotting room portal and deep shelter surface structures were levelled. The remains were pushed into the gunpits, entrance shaft and staircase respectively, and the site bulldozed over with a thick layer of soil from the surrounding land.

Burying the sound mirrors and the adits into the deep shelter was a different proposition, however. Attempts were made to demolish the sound mirrors, but were unsuccessful due to the strength of the reinforced concrete and the deep shelter emergency escape adits and latrine blocks alongside the sound mirrors remained visible for several years. The steep slope of Fan Hole meant that vehicle access was thought impossible.

However, in 1975, hundreds of tonnes of soil and chalk imported from other local sites were delivered by lorry and bulldozed over the steep slope to bury the adits and the mirrors. The site was then compacted and graded by a small bulldozer attached to a larger machine, by a thick wire hawser and was was left to be forgotten. The image below shows the land above Fan Hole being farmed, with no visible trace of the gun emplacements, plotting room, deep shelter or sound mirrors. The remains of the Wanstone and D2 batteries are hidden in the trees, top left.

Image of the White Cliffs of Dover from the air including the shallow bowl-shaped valley of Fan Hole
Fan Hole seen from the air after the site was covered over with soil in 1972. No trace of the sound mirrors or deep shelter can be seen | © National Trust Collection

Acquisition and deep shelter rediscovery

In 2012, the National Trust acquired the strip of land along the clifftops, from Langdon to South Foreland Lighthouse. The presence of Fan Bay Deep Shelter’s tunnels under this land was known, as erosion had opened a hole at the top of the staircase, but the entrance was difficult and not many people tried the treacherous descent. The land upon which the gun emplacements stood remained the property of the farmer and was out of bounds. The fate of the sound mirrors was unclear, as these were still covered in soil and completely invisible, with rumours that they had been toppled in Operation Eyesore.

In line with its conservation policy, the Trust secured the improvised entrance hole to the deep shelter with a horizontal steel door and undertook a detailed survey of the structure, as well as cataloguing artefacts and graffiti. As this was being done, a project proposal to excavate the tunnels and to open them to the public was being put together and submitted to the Trustees.


The project was a significant leap of faith since nothing like this had been undertaken by the Trust, but through much dedication and persuasion, the Trustees gave the go-ahead and excavation of the staircase began in the winter of 2013/4.

During 2014, investigation of the emergency exit adits started, and it was time to discover what was left, if anything, of the sound mirrors. In May 2014, a series of trial digs, by hand, revealed concrete about 1m below the surface, in the expected position for the sound mirrors.

In October 2014, work started on a highly technical and skilled project to excavate the mirrors and the adits. Over 600 tonnes of spoil were removed using specialist tracked dumpers on a perilous, temporary route down to the sound mirrors. By November, the north and south adit entrances, the remains of the latrine blocks and both sound mirrors became visible. Although the annecdotal story of the two bulldozers attached by hawser was regarded as highly improbable at the time, the hawser was discovered during the excavation of the adits and the method has since been verified by an eyewitness who took part in the work. Some of the remains of the hawser can now be seen ehibited in the tunnels.


The ground above the sound mirrors needed stabilising, and the adit entrances required reconstruction; alongside all the work to rebuild roof supports, the staircase and plant room entrances and make the site safe for the visitors to enter.

The shelter opened on 20 July 2015. A total of £117,000 had been spent along with over 3,500 volunteer hours on a pioneering project for the National Trust, which had spanned more than two years. Since the opening, over 50,000 visitors have taken guided tours of the Deep Shelter and sound mirrors.

But the mystery remained – what was the fate of the Fan Bay gun emplacements?

The Wanstone acquisition

During the summer of 2017, the opportunity arose for the National Trust to acquire the 178 acres (72 hectares) of land containing the D2 heavy anti-aircraft, Wanstone and Fan Bay gun emplacements and the Fan Bay plotting room. By September, the deal was done – these remains had a more certain future.

A detailed survey of the land behind Fan Bay Deep Shelter showed little evidence of the gun emplacements, save for several deep holes that led into the magazine tunnels and a heap of broken masonry, left from the 1972 demolition of emplacement number 1's superstructure.


During 2018, the plotting room entrance was discovered and a detailed graffiti survey was performed on the magazine tunnels, and the visible structures and compared to the original skeleton drawing of the site. The remains showed a strong possibility that at least some parts of the emplacements would have survived the 1970s demolition.

In 2019, plans were started for a project to excavate the 15-inch Wanstone and the 6-inch Fan Bay emplacements. The work would be partly financed by an application to the National Lottery Heritage Fund. Although the grant application had been submitted by the end of 2019, the Covid-19 pandemic placed the entire proposal on an indefinite hold.

The project starts

In January 2022, the team heard that the grant application had been successful – the £400,000 project would be funded by a £199,000 National Lottery grant, augmented by National Trust funds, generous local donations, partner organisations and volunteer effort. The project started in July 2022 with the successful excavation of one of the cross-channel gun emplacements, nicknamed ‘Jane’.

Image of a hole in the ground surrounded by grass which was the only way into the Fan Bay Number 3 emplacement magazine in 2018
The only visible trace of Fan Bay emplacement 3 - magazine entrance in 2018. Erosion and subsidence had caused this hole to open and access could be gained to the magazine tunnel | © National Trust/Richard Meadows

Exploration at Fan Bay

Spurred on by the success at ‘Jane’, plans were laid for the excavations at Fan Bay and in October 2022, an exploratory dig took place across the three emplacements.

The dig revealed that the three emplacement superstructures had been demolished almost down to gun ring level, and the remaining brickwork was badly damaged. The door frames to the rooms behind the guns – the men’s shelter, gun store and the ready-use lockers were visible with the compartments full of rubble. Much of the reinforced concrete roof and supporting masonry had been piled into the gun pits.

The good news was that the reinforced concrete emplacements, magazine tunnels and the magazines themselves appeared relatively unscathed. Number 3 emplacement would be the easiest of the three to fully excavate and to potentially turn into a visitor experience. The three emplacements were covered over again, with the magazine tunnels to numbers 1 and 2 guns permanently sealed, apart from small access apertures for bats and other creatures.

A full excavation of number 3 emplacement was planned for Summer 2023.

Excavations July 2023

On 10 July 2023, excavation started, and over 2 weeks, the emplacement was revealed. The work created considerable local and national interest and was recorded in detail for a programme in the ‘Digging for Britain’ series, broadcast in early 2024. Over 1000 visitors were shown around the site by the volunteer guides.

The reinforced concrete gun pit was found to be intact, along with the bolts for the gun mounting still projecting from the floor. The aiming marks in degrees were still clear, painted on the side wall of the emplacement. The entrances to the magazine, gun store, men’s shelter and the east and west ready-use ammunition lockers were uncovered, and the magazine was secured with a new heavy steel door. The east ready-use lockers were excavated, but the remaining rooms were judged to be too badly damaged to remain stable if uncovered and were left filled with debris.

It was decided to partly excavate number 2 gun emplacement down to the top level of the gun ring, to show the layout of the site.

Following excavation and a kind donation of railway sleepers, the volunteer team were able to stabilise the site prior to the winter, using the sleepers to construct walls to retain loose masonry, debris and soil.

Future plans

Details are still to be finalised; however, the intention is clear - that the Fan Bay emplacement will form a part of the overall Fan Bay experience for visitors, with guided tours operating during the season.

Back to Wanstone Rediscovered

Image of a circular concrete gun emplacement with the sea in the background
Fan Bay number 3 gun emplacement fully excavated looking seaward | © National Trust / Gordon Wise

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