The Emergency Coastal Defence Battery



  • One of the initial responses to the threat of invasion in May 1940 was the rapid establishment of Emergency Coastal Defence Batteries (ECDB) at places along the coast deemed to be vulnerable to attack, particularly those places that could provide a berth for enemy shipping.
  • The Royal Navy provided at total of nearly 200 six-inch guns that had been taken from ships scrapped after the First World War and then remained in store. The guns had been earmarked for use by merchant vessels, but they were soon mounted for coastal defence. The role of the batteries was as follows:


  1. To engage hostile vessels approaching within three miles of the coast and prevent them entering ports or harbours.
  2. To engage hostile vessels when beached so as to destroy their contents.
  3. To engage hostile vessels anchoring and prevent disembarkation from them.
  4. To destroy hostile small craft approaching the ports, harbours and beaches before they reach their objectives.
  5. In so far as it is compatible with their anti-craft role to assist field troops in their defence of the beaches.

Wartime aerial photograph

Wartime aerial photograph showing the entrance to the Blyth (With permission of English Heritage (NMR) RAF Photography). The elements of the ECDB are highlighted.
  • The core of an Emergency Coastal Defence battery was two separate gun houses (casements) with holdfasts for the guns set in concrete and storage space for ready-to-use ammunition. The gun and crew were protected, especially from air attack, by a structure to the front of the gun that often built of brick with a reinforced concrete roof.
  • Between and behind the casements were underground or partly sunken crew shelters and magazines. The shells and their propellant charges would usually be stored separately and brought to the gun by underground passages.


Gun Placement

The interior of a gun emplacement at an ECDB showing the gun being loaded. The Southwold battery would have looked something like this. (Imperial War Museum)


  • The battery also had an observation post that would often be a purpose-built structure, but sometimes placed in an existing building if it was of a suitable height. On either side of the guns there would be a Coastal Artillery Searchlight to illuminate targets. The searchlights were normally housed in concrete casements of sufficient strength to withstand small arms fire. The searchlight casement had a large aperture for the light and could be closed by a sliding metal shutter to protect it when not in use.
  • The searchlights were usually sited ahead and to each side of the gun houses and far enough above high water level to avoid salt spray. They also needed to be sufficient distance from the guns to avoid blast pressure. An engine house would also be constructed to protect the generators supplying electricity to the searchlights and the guns. The standard compliment for the battery was two officers and 60 other ranks, which included 34 gunners to operate the guns.
  • The battery was responsible for its own defence. The battery position was surrounded by barbed wire, trenches and each gunner was armed with a rifle. The beach in front of the battery was provided by anti-tank cubes, more barbed wire and Dragon's Teeth placed at the low water mark. A Lewis gun emplacement was manned throughout daylight hours ready to fire on low-flying enemy aircraft.


Costal Battery

The Emergency Coastal Defence Battery at Aldburgh firing one of its guns. The battery at Southwold would have been similar. (Imperial War Museum)


  • The Southwold battery has an interesting history. The guns were situated barely above sea level and due to problems caused by proximity to the sea, by January 1941 new locations were being investigated. The battery moved to Gun Hill, Southwold in September 1941, which was the highest part of the coastline in the immediate area. Wooden dummy armaments were placed in the empty gun houses and if the vacated accommodation was not being used by other troops then men from the Royal Artillery were occasionally to do outdoor training there to provide at least the pretence of occupation in the event of enemy reconnaissance.
  • Today nothing remains of this battery or any of the Second World War defences on the north side of the river Blyth; all were cleared away after 1945. Our evidence for this battery comes from aerial photographs, taken by both the Luftwaffe and RAF, interpretative maps produced by Suffolk County Council Archaeological Service and unit war diaries.