Operation Oyster  Operation Oyster was a bombing raid made by the Royal Air Force (RAF) on 6 December 1942 upon the Philips works at Eindhoven, Netherlands. The Philips company was a major producer of electronics equipment, including vacuum tubes for radio communication. Prior to the Battle of the Netherlands in 1940, Philips was known to be a leading research firm in infrared and radar technology. To ensure accuracy and minimise casualties among the Dutch citizens, the raid had to be undertaken during the day. Eindhoven was beyond the range of the fighter escort and the four-engined night bombers that made up the bulk of RAF Bomber Command were considered to be too vulnerable for the attack. No. 2 Group RAF which contained the medium day bombers of the RAF were selected for the raid. To improve their chance of survival, diversionary raids were organised to mislead the German defenders. Almost all of 2 Group was committed to the raid and it was the largest and most successful operation by the group of the war. In April 1942 the Air Ministry, in consultation with the Ministry of Economic Warfare, produced a list of the highest value targets in the occupied countries. Eight targets within range of the RAF were identified. The Philips radio and vacuum tube factory in Eindhoven was made the priority target, considered as important as any target in Germany. Philips was a leading firm in electronics and a big employer in Eindhoven, where production was performed at the massive Strijp works, and the smaller , half a mile away to the south-east. Prior to the war Philips made major advances in the design and production of vacuum tubes and had some of the best research scientists in the world. An appraisal by the Air Ministry estimated that the plants in Eindhoven produced a third of the radio tubes used in German military equipment. It was feared that the firm was being used to perform research into electronic counter-measures and radar technology.. The location of the Philips works in the middle of a Dutch city precluded Bomber Command from putting on a large scale raid at night, as this would result in a great many civilian casualties. For accurate bombing the target would have to be attacked during the day. Being inland from the coast, Eindhoven was beyond the range of fighter escort. Using Lancaster bombers for the raid was considered and rejected, as they were too vulnerable to fly through the middle of the German fighter belt in daylight. The use of de Havilland Mosquitos were also considered, but the Philips works was too large a target for the payload the Mosquitos available could carry.