Operation Glimmer was the codename for one of the deception operations used by the Allied forces during World War II in connection with the Normandy landings (Operation Overlord). In conjunction with Operation Taxable, this was conducted by aircraft of the Royal Air Force and small ships of the Royal Navy to trick the Germans into holding their forces in the wrong place. The aim of diversionary operations was to convince the defenders that the main invasion of France was directed at the Pas de Calais rather than Normandy.
The operation was carried out by G-H-equipped bombers flying tight circles at very low altitudes while dropping metal-foil strips of chaff (aka 'window' by the British at the time). Six 70-foot launches equipped with G-H transponders sailed beneath the aircraft, adding radio "chatter". The foil appeared on German radar as though a huge fleet of ships was approaching.
Operation Glimmer was undertaken by the Short Stirling bombers of No. 218 (Gold Coast) Squadron RAF aiming for Pas de Calais, at the same time as Operation Taxable was under way by the Avro Lancasters of the famous No. 617 Squadron RAF heading towards Cap d'Antifer. Both squadrons were tasked with precise, accurate flying, with the replacement aircraft having to fall into the circuits perfectly, so that the routine dropping of the "window" continued with neither overlap nor gap in the pattern.
218 Squadron were directed by the civilian physicist Sebastian Pease of Bomber Command's Operational Research Section to ensure that the deception was authentic.[1] It is to the credit of the pilots and navigators of 218 Squadron that the German shore batteries actually opened fire on the "ghost" fleet that they created. The German 2nd Panzer Division and 116th Panzer Division remained at the Pas de Calais for at least fourteen days after the invasion.
The RAF conducted another deception operation at the same time Operation Titanic which involved the dropping of dummy parachutists in the areas to the west and east of the Normandy landings.