The fourth Illustrious was one of the most distinguished ships of the Second World War. She was the first of a new class of Aircraft Carrier and was commissioned in 1940. HMS Illustrious spent only six months in the Mediterranean, but her involvement in that short space of time was to have far-reaching consequences, both locally and halfway around the world. Her first service of action was the Mediterranean in defense of the Malta convoys and where, on 11 November 1940, twenty Swordfish aircraft attacked the Italian Naval Base at Taranto. They inflicted severe damage on the Italian Fleet and helped to tip the balance of Mediterranean Sea power in favor of the Allies. Early in 1941, she suffered extensive damage and many casualties in a relentless attack by Stuka dive-bombers. After emergency repairs, she managed to escape to the United States where she was refitted and returned to active service in late 1941. After playing a major role in operations off Diego Suarez, Salerno and Sumatra, she supported the US landings at Okinawa. This was to be her final action of the war. After hostilities had ended, she returned to home waters as a training and trials ship before being laid up in 1954 and finally scrapped in 1957.
The Illustrious had a displacement of 28,619 tons, her dimensions were 753ft3in overall, 673ft at waterline, 106ft9in maximum beam, 95ft 9in at waterline, 28ft 2in draught at deep load, and her flight deck measured 740ft x 95ft 9in