Royal Navy ships and landing craft including eight destroyers. Royal Air Force 74 squadrons. The Netherlands. Over 6, infantry , predominantly Canadian, supported by a regiment of tanks, were put ashore from a naval force operating under the protection of Royal Air Force RAF fighters. The port was to be captured and held for a short period, to test the feasibility of a landing and to gather intelligence. German coastal defences, port structures and important buildings were to be demolished.
The raid was intended to boost Allied morale, demonstrate the commitment of the United Kingdom to re-open the Western Front and support the Soviet Union , fighting on the Eastern Front. The Luftwaffe made a maximum effort against the landing as the RAF had expected, and the RAF lost aircraft at least 32 to anti-aircraft fire or accidents against 48 German losses.
The Royal Navy lost 33 landing craft and a destroyer. Aerial and naval support was insufficient to enable the ground forces to achieve their objectives. The tanks were trapped on the beach and the infantry was largely prevented from entering the town by obstacles and German fire. After less than six hours, mounting casualties forced a retreat.
Within ten hours, 3, of the 6, men who landed had been killed, wounded, or taken prisoner. The operation was a fiasco in which only one landing force temporarily achieved its objective, and a small amount of military intelligence was gathered. Both sides learnt important lessons regarding coastal assaults. The Allies learnt lessons that influenced the success of the D-Day landings. Artificial harbours were declared crucial, tanks were adapted specifically for beaches, a new integrated tactical air force strengthened ground support, and capturing a major port at the outset was no longer seen as a priority.
Churchill and Mountbatten both claimed that these lessons had outweighed the cost. The Germans also believed that Dieppe was a learning experience and made a considerable effort to improve the way they defended the occupied coastlines of Europe.
