HMS Illustrious

Admiral Sir Reginald Henderson, Third Sea Lord, refused to repeat the unarmoured Ark Royal. Without early warning, he argued, nothing stopped land-based aircraft from reaching a carrier in confined waters like the North Sea or the Mediterranean, so the ship had to keep fighting after being hit and her aircraft had to be protected outright. The answer was to armour the hangar entirely, and the weight of that armour so high in the ship allowed only a single-storey hangar. It halved her aircraft capacity against the older carriers: offensive potential traded for survivability.

The flight deck carried three inches of armour, the hangar sides and ends 4.5 inches, the hangar deck 2.5 inches running the full width of the ship to meet the top of the 4.5-inch waterline belt. She was 740 feet long overall, displaced 23,000 tons standard, and her three Parsons turbines drove 111,000 shp for 30 knots; on trials on 24 May 1940 her engines made 113,700 shp. Her armament was sixteen 4.5-inch dual-purpose guns in eight twin turrets whose roofs stood above flight-deck level so they could fire across the deck.

Ordered from Vickers-Armstrongs in April 1937 and laid down at Barrow-in-Furness as yard number 732, she was slowed by armour deliveries from an industry starved of orders for fifteen years under the Washington Treaty; her flight-deck armour had to be ordered from the Vitkovice works in Czechoslovakia. She was launched on 5 April 1939, christened by Lady Henderson, and commissioned on 16 April 1940 at a cost of £2,295,000 excluding armament. Her completion was held back two months to fit a Type 79Z early-warning set, making her the first aircraft carrier in the world fitted with radar before completion.

She sailed for the Mediterranean on 22 August 1940 with fifteen Fulmars and eighteen Swordfish. Within weeks her aircraft had struck the Italian seaplane base at Rhodes, and on the moonlit night of 16 and 17 September fifteen Swordfish attacked Benghazi, 819 Squadron mining the harbour entrance while 815 Squadron sank the destroyer Borea and two freighters; the destroyer Aquilone struck one of the mines and sank. Rear Admiral Lumley Lyster, flying his flag aboard, proposed a carrier strike on the Italian fleet in Taranto, an idea the Royal Navy had studied since 1935, and Admiral Cunningham approved it by 22 September.

The attack was set for 21 October, the anniversary of Trafalgar, until a hangar fire aboard on 18 October destroyed three Swordfish and badly damaged two more, pushing it to 11 November and the next favourable moon. Eagle could not take part because of contaminated fuel tanks, and gave up her aircraft instead. Three Swordfish crashed on take-off on 10 and 11 November, probably from the same contamination, and the maintenance crews spent a day draining and refilling every tank. Twenty-one aircraft were left. Illustrious was detached with four cruisers and four destroyers to a point 170 miles south-east of Taranto.

Twelve aircraft, all she could launch at once, were away by 20:40, and nine more by 21:34. Six in each wave carried torpedoes, the rest bombs or flares to supplement a three-quarter moon. A Sunderland watching the harbour had already alerted the defenders, and the guns opened at 22:25. The first wave put one torpedo into Conte di Cavour and two into the new Littorio; the second hit Littorio again and Duilio once. Two Swordfish were shot down. Reconnaissance photographs next day showed three battleships with their decks awash in pools of oil. Conte di Cavour never returned to service.

On 10 January 1941, covering convoys to Piraeus and Malta, her fighters were drawn out of position chasing Italian torpedo bombers more than fifty miles from the ship. At 12:35, as four replacements launched, between 24 and 36 Ju 87 Stukas of I. Gruppe/StG 1 and II. Gruppe/StG 2 under Paul-Werner Hozzel began their attack. The first bomb struck just forward of the aft lift, destroying a Fulmar whose engine would not start and detonating high in the lift well. Five more hits followed in that attack.

One penetrated the unarmoured aft lift and destroyed it and the structure around it. Another destroyed a starboard pom-pom mount; another passed through a port mount without detonating but started a fire. The worst went through the deck armour forward of the aft lift and burst ten feet above the hangar deck, wrecking the rear sprinkler system, bending the forward lift like a hoop, shredding the fire curtains into splinters and blowing a hole in the hangar deck that damaged areas three decks below. A further attack at 13:20 hit the aft lift well again. She entered Grand Harbour at 21:04, still burning. The attacks killed 126 officers and men and wounded 91.

Malta gave no rest. On 16 January seventeen Ju 88s and 44 Stukas came for her, and a 1,100 lb bomb went through the flight deck aft of the rear lift and detonated in the captain's day cabin. On 19 January near misses dislodged enough hull plating to give an immediate five-degree list and cracked the cast-iron foundations of her port turbine. The naval historian J. D. Brown wrote that there is no doubt the armoured deck saved her from destruction, and that no other carrier took anything like this level of punishment and survived. Permanent repairs were made at the Norfolk Navy Yard in the United States from May 1941.

In May 1942 her aircraft covered the landings at Diego Suarez in Vichy French Madagascar. Before dawn on 5 May she launched eighteen Swordfish and eight Martlets: the first flight attacked the aviso D'Entrecasteaux without success but sank the armed merchant cruiser Bougainville, the second sank the submarine Beveziers with depth charges, the third dropped leaflets before attacking a battery. D'Entrecasteaux was bombed and run aground when she tried to put to sea. A patrolling Swordfish sank the submarine Le Heros the next morning, and on 7 May her Martlets shot down three Morane-Saulnier fighters for the loss of one. Her aircraft flew 209 sorties.

From January 1944 she worked from Trincomalee against Japanese-held targets. With the American carrier Saratoga she struck Sabang in northern Sumatra on 19 April, her seventeen Barracudas and thirteen Corsairs hitting shore installations while the Americans worked the harbour; the oil tanks were destroyed and 24 aircraft claimed on the ground. Operation Transom against Surabaya on 17 May needed Avengers in place of the shorter-ranged Barracudas and a refuelling stop at Exmouth Gulf in Western Australia. Port Blair followed in June, and on 25 July her 22 Corsairs spotted for the fleet's guns as they wrecked Sabang's oil storage and port.

In January 1945, sailing for Sydney, the carriers of the 1st Aircraft Carrier Squadron attacked the Palembang refineries. Illustrious contributed twelve Avengers and sixteen Corsairs on 24 January, an attack that destroyed most of the oil storage and halved output for three months, and twelve of each on the 29th. Between the two operations her squadrons lost six Corsairs and three Avengers. As the strike aircraft were landing on, seven Japanese bombers came in; all were shot down, but the fleet's fire discipline was poor and two shells from Indomitable or King George V struck Illustrious, killing twelve men and wounding 21.

As part of Task Force 57 she flew against the Sakishima airfields between Okinawa and Formosa from 26 March 1945. On the afternoon of 6 April a Yokosuka D4Y kamikaze evaded the patrol and dived on her; her light guns severed its port wing so that it missed, its starboard wingtip shattering the Type 272 radome on the bridge front, and its 1,000-kilogram bomb detonated in the water fifty feet from her side. The first assessment found little harm. It was wrong: divers at San Pedro Bay found outer plating split and transverse frames cracked.

The damage sat on top of years of it. By early 1945 undiagnosed shock damage had set up such vibration in her centre propeller shaft that the propeller was removed and the shaft locked, cutting her to about 24 knots. Since the beginning of the Okinawa operation her aircraft had flown 234 offensive and 209 defensive sorties. Formidable was ordered up to replace her on 8 April. She sailed for Sydney on 3 May and reached Britain on 27 June, and when the war ended in August the Admiralty turned her repairs into a refit and made her the Home Fleet's trials and training carrier.

In that role she took the first deck landings of most of the Royal Navy's post-war aircraft: the prototype Supermarine Attacker jet in October 1947, the de Havilland Sea Vampire and Sea Hornet, and on 16 June 1950 the prototype Fairey Gannet, the first turboprop aircraft ever landed aboard a carrier. On 8 and 9 November 1950 the Supermarine 510 made the first landings by a swept-wing aircraft aboard any carrier. She spent 1953 trialling the mirror-landing system that automated the approach, and in November 1951 carried the 39th Infantry Brigade and then a second lift of troops to Famagusta during the Cyprus riots.

She was reunited with the four other carriers of the British Pacific Fleet for the first time since the war at the Coronation Fleet Review at Spithead on 15 June 1953. Her last landings were made on 3 December 1954. She was paid off at the end of February 1955, towed to the Gareloch and laid up, sold on 3 November 1956 and broken up early the following year.