She set sail on her fourth and final voyage from Glasgow on 2 June 1941, destined for Alexandria, Egypt. The vessel's cargo included: Bedford trucks, Universal Carrier armoured vehicles, Norton 16H and BSA motorcycles, Bren guns, cases of ammunition, and 0.303 rifles as well as radio equipment, Wellington boots, aircraft parts, railway wagons and two LMS Stanier Class 8F steam locomotives. These steam locomotives and their associated coal and water tenders were carried as deck cargo intended for Egyptian National Railways. The rest of the cargo was for the Allied forces in Egypt. At the time the "Thistlegorm" sailed from Glasgow in June, this was the Western Desert Force, which in September 1941 became part of the newly formed Eighth Army. The crew of the ship, under Captain William Ellis, were supplemented by nine naval personnel to man the machine gun and the anti-aircraft gun.