Many locations in Suffolk did not have adequate public or private shelters to protect the local population in the event of invasion or raids. As a result, it was recommended that householders should dig slit trenches in their gardens for such circumstances.
Guidance was issued on how to dig slit trenches and in some cases the Home Guard would dig examples for the public to follow (e.g. at Haverhill on ‘Stand To’).
A pamphlet in the Suffolk Records Office states that “Narrow trenches, known as slit trenches, have found by experience to give a high degree of protection from Artillery fire and dive-bombing attack, to which we may be subject to in the event of invasion”. The pamphlet goes on to state that all those that can should dig slit trenches when the time comes.
Recommended dimensions were two feet wide and three feet deep. For each person, 2 feet 6 inches length should be allowed and they should be at least 15 feet away from any building. The spoil should be piled up on either side, approx. 1 foot 6 inches high. They could be lined with timber, old doors, corrugated iron sheets or any other similar material that was at hand.
The pamphlet warns against digging trenches too soon before they are needed due to the risk of erosion and collapse. It recommends marking out trenches on the ground and perhaps digging the first foot to save time in an emergency. Finally it is recommended to have a garden spade available when required!
Above: Recommended dimensions for Slit Trenches (and Breast Works in poor soil conditions)
References: Debenham Invasion Committee papers, SRO