Editing Concertina wire (section)

== Dannert wire ==
Oil-tempered barbed wire was developed during World War I; it was much harder to cut than ordinary barbed wire. During the 1930s,<ref>[https://patents.google.com/patent/DE599829C/de] 1934 German patent</ref> German Horst Dannert developed concertina wire of this high-grade steel wire.{{sfn|Lewis|2014|p=93}} The result was entirely self-supporting; it did not require any vertical posts.<ref>Dannert, Horst. Improvements in Barricades. British Patent No 480,082. 1937.</ref> An individual Dannert wire concertina could be compressed into a compact coil that could be carried by one man and then stretched out along its axis to make a barrier {{convert|50|ft|m}} long and each coil could be held in place with just three staples hammered into the ground.<ref name = "WO Dannert" >{{Cite book
 | title      = Construction of Dannert Concertina Wire Obstacles
 | publisher  = War Office
 | series     = Military Training Manual No 21A
 | date       = September 1939
}}</ref>

Dannert wire was imported into Britain from Germany before World War II.{{sfn|Metcalfe|Buchanan-Redden|1997|p=4}} During the [[British anti-invasion preparations of World War II|invasion crisis of 1940–1941]], the demand for Dannert wire was so great that some was produced with low manganese steel wire which was easier to cut. This material was known as "Yellow Dannert" after the identifying yellow paint on the concertina handles. To compensate for the reduced effectiveness of Yellow Dannert, an extra supply of pickets were issued in lieu of [[screw picket]]s.<ref>{{cite web
 | url          = http://pillboxes-suffolk.webeden.co.uk/#/wire-obstacles/4537170353
 | title        = Defence Works: Wire Obstacles
 | work         = Anti-invasion defences of Suffolk: World War II
 | access-date  = 19 September 2010
 | archive-date = 24 August 2011
 | archive-url  = https://web.archive.org/web/20110824121014/http://pillboxes-suffolk.webeden.co.uk/#/wire-obstacles/4537170353
 | url-status   = dead
}}</ref>