World War II minefield control tower 940m and pillbox 980m south east of Holliwell Farm


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:


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The building or site itself may lie within the boundary of more than one authority.

Maldon (District Authority)
National Grid Reference:
TR0166295813, TR0168895777

Reasons for Designation

In the years prior to the outbreak of World War II Burnham-on-Crouch was of little significance to the Royal Navy, although a small minefield had been laid in the estuary during World War I. However, after the German occupation of France, this comparatively small yachting centre suddenly aquired a greater significance, representing a possible landing point for enemy forces seeking a short and undefended route to London. In 1940 the British Army had already constructed a series of pillboxes along the sea wall as part of its coastal defence scheme (which also included measures such as anti-aircraft gunsites and bombing decoys). The Royal Navy sought to make the River Crouch inaccessible to enemy invasion craft (at that time the river would have admitted vessels of up to 22 feet(6.7m) draught) and constructed a floating boom defence of wire ropes and buoys. The next step was to lay mines in the estuary at the gateway to the boom defence. The two wartime structures at Holliwell Point give testimony to this particular and most important aspect of the defensive scheme.

Built in 1940 the pillbox predates the minefield control tower. Originally one of a series of manned defensive pillboxes along the coast, it undertook a more specialised role in housing the firing equipment for the original two warheads deployed at Holliwell Point. With the expansion of the minefield in 1941 the impressive control tower was purpose-built. This is a highly unusual structure, unique in England. The only other surviving example of a purpose-built minefield control tower in the British Isles overlooks the Sound of Kerrera, 4.8km south of Oban in Scotland.

The minefield control tower survives in particularly good condition and provides a unique record of the architecture and design of this type of combined observation/control post. The pillbox is its improvised forerunner and has an important role to play in illustrating the evolution of the full complement of defensive schemes employed here. Together the two structures provide a graphic illustration of the threat, acutely felt at the time, of the impending German invasion.


The monument is situated on the Dengie Peninsula 940m and 980m south east of Holliwell Farm. It includes a fortified observation tower and a double-ended pillbox, both at the mouth of the River Crouch on its northern bank, enclosed within two separate areas of protection. The tower stands on the edge of an open field adjacent to the sea wall; the pillbox is built into the sea wall some 15m to the south east of the tower.

In 1941 the main function of both structures was to control the estuary minefield which defended the River Crouch at this point. The observation tower is a two-storey hexagonal tower, constructed of concrete and brick with walls 0.6m thick, measuring 14m by 10m in plan and 10m high, surmounted by a cupola. The lower level was easily defended with a single entrance, complete with steel door, in its western side. A total of 17 machine gun apertures at two different heights give a 360 degree defensive capability. The apertures originally had steel shutters which could be closed when under sustained attack; two of these are still in place.

The upper floor (measuring 5m at its widest point) is reached from below by an open hatchway and has a high pyramidal ceiling with the concrete cupola forming its apex. The upper floor has a number of defensive positions: a concrete platform gives access to a high look-out slot in the southern wall which affords a view across the whole of the mouth of the River Crouch; the cupola has a firing slot in each of its six sides, giving all-round views across the surrounding flat landscape. All of the firing slots in the cupola have steel shutters which could be closed when under direct attack.

The pillbox is built into the sea wall and has apertures both facing the estuary and facing the control tower which lies 15m inland. The seaward, southern end, has the entrance and five gun apertures, one of which retains its original steel flap. At the landward, northern end, there are three apertures looking back towards the control tower. The whole structure is 15m long by 5m wide, with its long axis orientated north east-south west, bisecting the sea wall.

In 1940, after the German occupation of France, Burnham-on-Crouch became of serious interest to both the Royal Navy and the British Army as a possible scene of an attempted landing by enemy forces seeking to find a short and undefended passage to London. The River Crouch offered just such a passage, by-passing the main defences of the Rivers Thames and Medway.

The pillbox at Holliwell Point was one of a number of military pillboxes constructed at the beginning of the War as a vital component of the coastal defences. In 1940 the Royal Navy sought to strengthen the coastal defences by laying mines in the estuary. In July 1940 approval was given for warheads, connected to electrical firing, to be laid as mines, pending the supply of a more permanent minefield; the electrical firing equipment was set up in the already existing pillbox. In August 1940 at a conference held at Admiralty House, Chatham, it was decided to lay eleven groups of three mines each to supplement the warheads already at Holliwell Point. In June 1941 the control tower was built, together with the quarters for a complement of two Royal Naval Volunteer Reserve Officers, six wiremen and sixteen Royal Marines as guards. On the 15th November 1941 the accommodation block was seriously damaged by the explosion of a parachute mine, one of four dropped by enemy aircraft. With the threat of a German invasion a constant concern for most of the wartime period, and the River Crouch providing a potential access point, the minefield control tower continued to be manned for the duration of the War.

All modern fences, fence posts and concrete culverts associated with the sea wall are excluded from the scheduling, although the ground beneath them is included.

MAP EXTRACT The site of the monument is shown on the attached map extract. It includes a 2 metre boundary around the archaeological features, considered to be essential for the monument's support and preservation.


The contents of this record have been generated from a legacy data system.

Legacy System number:
Legacy System:


Books and journals
War Time Contraventions, (1968)
Foynes, J P, The Battle of the East Coast (1939-1945), (1994), 253
Foynes, J P, The Battle of the East Coast (1939-1945), (1994), 253
Kent, P, Fortifications of East Anglia, (1988), 67
Nash, F, 'After the Battle' in World War Two Defences in Essex, , Vol. 116, (2002), 30-5
2.4.93 colour prints, Rogers, P, 748-3, 4, (1993)
2.4.93, Rogers, P, 748-3, 4, (1993)
Black and white print, Strachan, D, BW/99/25/1, (1999)
Nash, F, 1 Frame in ECHR, (1995)
Nash, F, 7 Frames, (1995)
Part of document on HMS Leigh;in ESMR, Captain CR Dane, Burnham-on-Crouch (R.N.O. Burnham) June 1940-June 1945, (1940)
Part of document on HMS Leigh;in ESMR, Dane, C R, Burnham-On-Crouch (R.N.O. Burnham) June 1940-June 1945, (1940)
Strachan, D, BW/99/25/1, (1999)


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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