- In May 1940 when invasion was thought imminent there were just two field batteries, each of four guns, defending the coastal area between the Rivers Alde and Blyth. Firepower was increased rapidly through the summer and by the autumn there were six field batteries, with a total of 24 guns.
- There were three artillery units that could fire on the area around Walberswick: 136 Field Regiment, 72 Medium Regiment and 53 Heavy Regiment. The latter two were grouped together for operational purposes. Their constituent Batteries and Troops were an important part of the coastal crust.
- 136 Field Regiment was the primary artillery unit assigned to defend the coast from Aldeburgh to the River Blyth including the area around Walberswick. During August the regiment were still short of their full complement of guns but then, in the third week of the month, they were supplied with fifteen 75mm French built guns of the First World War, with a sixteenth gun delivered later.
- It was an easy gun to operate and a trained gun crew could fire up to 30 rounds a minute, with up to six shells in the air at any one time. It was found to be very accurate and was held in high esteem by the gunners, firing a 16lb shell to a maximum range of 7,500yds.
- The gun did, however, have a maximum elevation of only seventeen degrees, which meant that they had to be kept well clear of buildings and trees and inevitably ended up being in the centre of a field. Despite being camouflaged with netting, positions would have been clear from the air and detachments at that time felt very exposed.
A 75mm Field Gun and crew in training in Scotland in 1941. At Walberswick each gun had its own gun pit, with camouflage netting overhead. (Imperial War Museum)
- ‘E’ Troop of 348 Battery 136 Field Regiment with its four guns was positioned close to Sallow Wood Covert. The troop would probably have been commanded by a captain with a total all ranks, including Troop HQ, of about 63 men.
- Their prime task was to fire on enemy vessels as they approached the coast and on the beaches in the event of the invaders obtaining a footing. In this sense, the guns were very much infantry support weapons, in place to give an intense boost of firepower to those in the section trenches. The guns were also tasked with firing on paratroopers who landed behind the invasion beaches and had an important anti-tank role in the case of a full-scale invasion.
- The four guns were arranged in a staggered row, each in its own separate pit, but the nature of their tasks meant that the gunners had to be prepared to change their direction of fire or be able to tow their guns to targets elsewhere. For this reason it was necessary for the pits to be large enough and comparatively shallow.
- They would have been surrounded by a low wall built up from the removed spoil together with sandbags to give some protection for the crew against shrapnel or small arms fire. To camouflage individual guns from the air they would be covered with net scrim supported by posts and guyed at the side.
- All artillery positions, particularly this isolated battery, had to be protected for all round defence and often, as is the case with this battery, by gunners acting as infantry equipped with small arms. The whole gun position was also surrounded with barbed wire. As for the Emergency Coastal Defence Battery, a Lewis gun emplacement provided both anti-aircraft and, in an emergency, ground defence.
- The arc of fire of the battery was the coastline between Cox’s Farm to the north of Southwold town and Sandymount Covert to the south of Walberswick. There were two ‘SOS’ tasks or special target areas; SOS tasks being pre-arranged defensive fire on areas considered to be the most vulnerable. One was on the beach in front of the village of Walberswick and the other on the beach just to the north of the River Blyth.
- A forward platoon commander who found himself under attack would fire an SOS signal, at that time a golden rain rocket, and immediate defensive fire would be brought down on the allocated target, closest to the point at which the signal was sent up.
- 78 Medium Regiment was Royal Artillery based at Henham park and was grouped with 136 Field Regiment for operational purposes. Their arc of fire was between Eastern Broad and Sandymouth Covert. Their ‘SOS’ Task was just to the north of Southwold.
Map showing the arcs of fire and 'SOS' tasks of troops from 72 Medium Regiment and 136 Field Regiment, Royal Artillery and Observation posts.
- In order to be effective, batteries had to have forward observers close to the beach so they could locate targets and relay important information to the battery some distance behind. For this purpose, several artillery obersvation posts were constructed. Two of these survive at Walberswick and both are closely related to infantry positions.