Operation Grün (Ireland)

Operation Green (German: Unternehmen Grün) often also referred to as Case Green (Fall Grün) or Plan Green (Plan Grün), was a full-scale operations plan for a Nazi German invasion of Ireland in support of Operation Sea Lion (Unternehmen Seelöwe), the invasion of the United Kingdom, during World War II. Despite its detailed nature, Green is thought to have been designed only as a credible threat, a feint, not an actual operation. Plan W, a planned occupation of all of the state by the British Armed Forces, was drafted by the British military in secret liaison with the Irish government to counteract any German invasion.

German interest in Green and Operation Sea Lion must always be understood in the context of their overall strategic plan. That, first and foremost, was Operation Barbarossa, the invasion and destruction of the Soviet Union. They had little interest in tying up military resources in Britain or France, other than doing what was necessary to prevent the British and French from interfering with the invasion of the Soviet Union. During Britain's darkest hour, therefore, the Germans were, in fact, secretly marshalling most of their resources to attack their ally in the occupation of Poland: the Soviet Union.

Implementation of Green was the responsibility of General der Artillerie Leonhard Kaupisch, commander of the German Fourth and Seventh Army Corps, Army Group B. The originator of the idea for Green is thought to be newly promoted Generalfeldmarschall Fedor von Bock, Army Group B. Bock had operational command for the western flank under Operation Sea Lion. Once collated, thirty-two copies of Green were distributed as "Top Secret" on 8 August 1940 to the German High Command; a number of copies survived World War II.

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