As commander of Combined Operations, Mountbatten and his staff planned the highly successful Bruneval raid, which gained important information and also captured part of a German Würzburg radar installation and one of the machine's technicians on 27 February 1942. It was Mountbatten who recognized that surprise and speed were essential to ensure the radar was captured, and saw that an airborne assault was the only viable method. He was in large part responsible for the planning and organisation of The Raid at St. Nazaire in mid-1942, an operation which put out of action one of the most heavily defended docks in Nazi-occupied France until well after war's end, the ramifications of which contributed to allied supremacy in the Battle of the Atlantic. After these two successes came the Dieppe Raid of 19 August 1942. He was central in the planning and promotion of the raid on the port of Dieppe. The raid was a marked failure, with casualties of almost 60%, the great majority of them Canadians. Following the Dieppe raid Mountbatten became a controversial figure in Canada, with the Royal Canadian Legion distancing itself from him during his visits there during his later career. His relations with Canadian veterans, who blamed him for the losses, "remained frosty" after the war.