The expected invasion of Britain was considered most likely to combine an invasion force landing on the beaches combined with parachute and glider troops landing inland. The German invasion of Holland and Norway showed that planes could land several thousand men per hour. As well, gliders could carry 10-12 men along with one heavy machine gun, one light machine gun plus ammo and rifles etc. A Junkers 52 could tow between three to six gliders and once releasing them fly back for more.
Following the evacuation from Dunkirk, the Home Executive were tasked with constructing anti-landing obstacles as a matter of urgency. Hence as a result, many anti-landing obstacles were built along potential invasion coasts typically either trenches or poles arranged in a grid pattern. Instructions from 11 Corps stated that any potential landing ground, within five miles of practical landing beaches or within five miles of Walberswick and Lowestoft, were to be made unfit to land on.
Potential Landing grounds could be obstructed by the following methods:
1. by trenches dug on a chequer board pattern with sides of 150 yards (approved method issued by War Office on 27th May 1940) . The trenches were to be four ft wide flanked with spoil piles to enhance the obstacle. In Suffolk, vast areas of potential landing grounds such as heathland and cultivated land were covered by trenches.
2. by placing old motor vehicles, with the wheels removed, or other obstacles criss-cross over the ground. For example beach huts were strewn accross the common at Southwold.
Crops were not to be destroyed by digging trenches. Eastern Command War Diary notes a scaffolding pole obstacle was to be used although this was probably not carried out in practice.
Potential landing grounds also included main roads which had a straight run of 600 yards and 90 ft in width. These could be obstructed by overhead wires 20 ft above the ground at 300 yard intervals. Concrete blocks were not to be placed on the road but could be erected on alternative sides at 150 yard intervals. Not many roads, if any at all, in Suffolk within five miles of the Coast had such a straight run so it is unlikely this obstacle was required.
Left: Remains of anti-landing trenches,
Aldringham Walks. The chequer board pattern
and spoil piles can clearly be seen.
Below: Anti-landing trench, Walberswick
Invasion Tactics, Dr W Necker, Bernards Ltd, 1944
The Home Guard Training Manual, Major J Langdon-Davies, John Murray & The Pilot Press, 1942
11 Corps papers, TNA