The St Nazaire Raid or Operation Chariot was a British amphibious attack on the heavily defended Normandie dry dock at St Nazaire in German-occupied France during the Second World War. The operation was undertaken by the Royal Navy and British Commandos under the auspices of Combined Operations Headquarters on 28 March 1942. St Nazaire was targeted because the loss of its dry dock would force any large German warship in need of repairs, such as Tirpitz, sister ship of Bismarck, to return to home waters by running the gauntlet of the Home Fleet of the Royal Navy and other British forces, via the English Channel or the GIUK gap.