The Valentin factory was attacked by the RAF on 27 March 1945. The attacking force consisted of twenty Avro Lancaster heavy bombers of 617 Squadron which had, after the "Dambusters" raid, developed precision bombing methods. Simultaneously, a force of 115 Lancasters bombed the nearby fuel oil storage depot in the village of "Schwanewede". The bombers were escorted by ninety RAF North American Mustang fighters of 11 Group