The standard British wire obstacle was the double apron fence, which consisted of three horizontal strands on the fence and three on each apron. Two or three rows of double apron formed a very effective obstacle and was not easily destroyed by shellfire. Typically the wire would be fixed to screw pickets but wooden posts or angle iron could be used. The gaps between double aprons were often filled a Dannert concertina wire fence. Dannert wire was the term retained by the British for oil tempered barbed spring-steel coil concertina wire introduced by the Germans in WW1 by Herr Dannert. Between May and November, 55th Div constructed over 200 miles of wire obstacles.
From Manual of Field Works (All Arms) 1925
Wire pickets - left and central are WW2
while right is WW1 (recovered from the
Triple concertina (Dannert Wire ) fence - Field Engineering and Mine Warfare - Field Defences and Obstacles 1951
Left and above: Triple Concertina fences
The war diary of 7th Royal Sussex (Operational Instruction No. 19, Jul 1941) notes that in order to meet demands of Dannert Wire, 25% was produced with low manganese steel wire. This was a softer metal and easier to cut. The handles of these concertinas were painted yellow and the wire was known as "Yellow Dannert" in order for easy reference. In order to compensate for the reduced effectiveness of the wire, an extra supply of angle iron pickets as well as long forestry pickets were issued in lieu of screw pickets
Another wire obstacle given in the manuals of the time is spider wire, normally three strand ‘cattle’ fences arranged to divide the ground into compartments. I have found no mention in unit diaries to indicate this type of obstacle was used.
Most Brigade Defence Schemes stipulate a single wire obstacle (although they do not state the nature of the wire obstacle) for locations larger than platoons (e.g. towns and villages). For platoon localities the standard wire obstacle was a Dannert fence between two double apron fences. However in 1941, 37 Brigade was stipulating two triple Dannert wire fences and one double apron fence to form a single obstacle.
Double apron fences were highly visible from the air. Indeed the staff of 55th Div noted that many pillboxes and posts were betrayed by rings of wire. Military Training Pamphlet No 46 Part II Camouflage of Field Defences states that wire obstacles should follow hedge or ditch lines if possible. An angular layout would be more likely fit into the surrounding countryside rather than a circular layout, although would involve a greater usage of materials and labour. There are frequent references in the home forces diaries of units based in Suffolk which state that on no account should wire be sited in circular layouts (although aerial photos taken in 1940 show that wire was oftten sited in such a manor!).
Today, the typical remains of wire obstacles in Suffolk consist of the odd iron screw picket in hedgerows, scrub or on coastal heaths. Rarely, large ‘dumps’ of barbed wire can be found often in hollows (e.g. Westleton Walks) or in the bottom of trenches (e.g. North Warren) where wire was obviously cleared and conveniently dumped after the war.
55th Div papers, NRA
37 Brigade papers, NRA
7th Royal Sussex papers, NRA
Military Training Pamphlet No 46 Camouflage Part II Field Defences, War Office 1941
Manual of Field Works (All Arms), War Office, 1925
Field Engineering and Mine Warfare Pamphlet No 2, Field Defences and Obstacles, War Office, 1951