The 'Battle of Taranto', otherwise known as the 'Judgement' operation, was a naval air/sea battle fought between British carrierborne aircraft of Admiral Sir Andrew Cunningham’s Mediterranean Fleet and Italian warships of Ammiraglio di Squadra Inigo Campioni’s Italian fleet in the harbour of Taranto in southern Italy (11/12 November 1940).

In this battle, the British launched the first all-aircraft ship-to-ship naval attack in history, employing 21 Fairey Swordfish single-engined torpedo-bomber biplanes from the fleet carrier Illustrious in the Mediterranean Sea. The attack struck the battle fleet of the Regia Marina at anchor in the harbour of Taranto, using air-launched torpedoes despite the shallow nature of the water. The success of this attack augured the ascendancy of naval aviation over the big-gun battleship. According to Cunningham, 'Taranto, and the night of 11-12 November 1940, should be remembered forever as having shown once and for all that in the Fleet Air Arm the Navy has its most devastating weapon.'

Since long before World War I, the Italian Regia Marina’s 1a Squadra had been based at Taranto, a port city in the 'arch' of the 'foot' of Italy’s south-eastern coast. In the period between the two world wars, the British Royal Navy developed plans to counter the Italian navy in the event of a war in the Mediterranean. Plans for the capture of the port at Taranto were considered as early as the Italian invasion of Abyssinia in 1935.

After Italy’s entry into World War II in June 1940, British and Italian forces in North Africa fought the Western Desert land campaign. Italian troops based in the Italian colony of Libya required a supply line from Italy. British troops, based in Egypt, suffered from much greater supply difficulties. Before Italy entered the war, British convoys had travelled along the Mediterranean, from Gibraltar via Malta to Egypt, but then the threat posed by the Italian navy and air force made this very difficult. Instead, British ships steamed around the Cape of Good Hope, north along the eastern coast of Africa, and then through the Red Sea and finally the Suez Canal to reach Alexandria on the northern coast of Egypt.

Adherents of the concept of a fleet in being, the Italians usually kept their warships in harbour and were unwilling to seek battle with the Royal Navy on their own: part of the Italian thinking stemmed from the fact that the loss of any warship larger than a destroyer exercised a major influence as it could not be replaced. The Italian fleet at Taranto was powerful: six battleships, of which Andrea Doria was not yet battle-worthy as her crew was still in training after the ship’s reconstruction, seven heavy cruisers, two light cruisers and eight destroyers. This made the threat of a sortie against their shipping a matter of serious concern for the British.

During the Munich Crisis of 1938, Admiral Sir Dudley Pound, then the commander of the British Mediterranean Fleet, was concerned about the survival of the aircraft carrier Glorious in the face of Italian opposition in the Mediterranean, and ordered his staff to re-examine all plans for attacking Taranto.Pond was advised by Captain A. L. St G. Lyster, the captain of Glorious, that his ship’s Swordfish torpedo-bombers were capable of a night attack. Indeed, the Fleet Air Arm was then the only naval aviation arm with such a capability. Pound took Lyster’s advice and ordered training to begin. Security was kept so tight there were no written records. Just a month before the start of the war, Pound advised his successor, Admiral Sir Andrew Cunningham, to consider the possibility of what became 'Judgement'.

The fall of France in June 1940 and the consequent loss of the French fleet in the Mediterranean (even before the British attack on its in 'Catapult'. made redress essential. The older carrier Eagle, on Cunningham’s strength, was ideal, possessing a very experienced air group composed entirely of the obsolescent Swordfish aircraft. Three Gloster Sea Gladiator single-engined biplane fighters were added for the operation. Firm plans were drawn up after the Italian army halted its eastward movement at Sidi Barrani, which freed the Mediterranean Fleet for other purposes.

'Judgement' was just a single element of the overarching 'MB8' undertaking. It was originally scheduled to take place on 21 October, but a fire in an auxiliary fuel tank of one Swordfish led to a delay, during which time a 60-imp gal (270-litre) auxiliary tank was installed in the observer’s position on torpedo-bombers, the observer then taking the air gunner’s position, in order to extend the operating range of the aircraft sufficiently to reach Taranto. This minor fire spread into something more serious that destroyed two of the embarked Swordfish aircraft. Eagle then suffered a breakdown in her fuel system, and had therefore to be removed from the operation.

When the new carrier Illustrious, based at Alexandria, became available in the Mediterranean Sea, she took on board five Swordfish aircraft from Eagle and launched the attack alone.

The complete naval task force, led by Lyster, now a rear admiral and who had originated the plan of attack on Taranto, comprised Illustrious, the heavy cruisers Berwick and York, the light cruisers Gloucester and Glasgow, and the destroyers Hyperion, Ilex, Hasty and Havelock. The 24 Swordfish aircraft came from Nos 813, 815, 819 and 824 Squadrons. The small number of attacking warplanes raised concern that 'Judgement' would only alert and enrage the Italian navy without achieving any significant results. Illustrious also had Fairey Fulmar single-engined fighters of No. 806 Squadron aboard to provide air cover for the task force, and also carried radar and fighter-control systems.

Half of the Swordfish aircraft were armed with torpedoes as the primary attack aircraft, with the other half carrying free-fall bombs and flares to carry out diversions. The torpedoes were fitted with Duplex magnetic/contact exploders, which were extremely sensitive to rough seas, as the attacks on the German battleship Bismarck later showed. There were also concerns that the torpedoes would bottom out in the shallow water of the harbour after being dropped. The loss rate for the bombers was expected to be one in two.

Several reconnaissance flights by Martin Maryland twin-engined aircraft of the RAF’s No. 431 General Reconnaissance Flight, flying from Malta, confirmed the location of the Italian naval force in Taranto. These flights produced photographs on which the intelligence officer of Illustrious spotted previously unexpected barrage balloons. The attack plan was therefore changed to take account of this fact. To make sure the Italian warships had not sortied, the British also despatched a Short Sunderland four-engined flying boat on the night of 11 November, just as the carrier task force was forming up off the Greek island of Kephalonia, about 200 miles (320 km) from Taranto. This reconnaissance flight alerted the Italian forces in southern Italy, but since they were without radar, they could do little but wait. The Regia Marina could conceivably have gone to sea in search of any British naval force, but this was distinctly against the naval philosophy of the Italians between January 1940 and September 1943.

The complexity of 'MB8', with its various forces and convoys, succeeded in deceiving the Italians into the belief that it was only normal convoy undertaking that were under way, and thus made an important contribution to the success of 'Judgement'.

The base of Taranto was defended by 101 anti-aircraft guns and 193 machine guns, and was usually protected against low-flying aircraft by barrage balloons, of which only 27 were in place on 11 November as strong winds on 6 November had blown away 60 balloons. Capital ships were also supposed to be protected by anti-torpedo nets: 14,000 yards (12800 m) of netting were required for full protection, but only one-third of this total had been rigged before the attack asa gunnery exercise had been scheduled. Moreover, these nets did not reach the bottom of the harbour, allowing the British torpedoes to clear them by about 2 ft (0.6 m).

The first wave of 12 aircraft, led by Lieutenant Commander Kenneth Williamson of No. 815 Squadron, lifted off Illustrious just before 21.00 on 11 November, followed by a second wave of nine similar aircraft about 90 minutes later. Of the aircraft of the second wave, one turned back as its auxiliary fuel tank detached from the aircraft, rendering the aeroplane incapable of completing the trip, and one launched 20 minutes late after requiring emergency repairs to damage following a minor taxiing accident, so only eight made it to the target.

The first attacking wave, which comprised six Swordfish aircraft armed with torpedoes, two with flares and four 250-lb (112-kg) bombs, and four with six bombs, was split into two sections when three of the bombers and one torpedo-bomber strayed from the main force while flying through thin cloud. The smaller group continued to Taranto independently. The main group approached the harbour at Mar Grande at 22.58. Some 16 flares were dropped to the east of the harbour, then the flare dropper and another aeroplane made a dive-bombing attack to set fire to oil tanks. The next three aircraft, led by Williamson, attacked over San Pietro island and struck the battleship Conte di Cavour with a torpedo that blasted a 27-ft (8.2-m) hole in her side below the waterline. Williamson’s aeroplane was immediately shot down by the Italian battleship’s anti-aircraft guns. The two remaining aircraft in this sub-flight continued, dodging barrage balloons and receiving heavy anti-aircraft fire from the Italian warships and shore batteries, to press home an unsuccessful attack on the battleship Andrea Doria. The next sub-flight of three attacked from a more northerly direction, targeting the battleship Littorio, hitting her with two torpedoes, and launching one torpedo at the flagship, the battleship Vittorio Veneto, which missed. The bomber force, led by an officer of the Royal Marines, Captain O. Patch, attacked next. They found the targets difficult to identify, but attacked and hit two cruisers moored at Mar Piccolo, hitting each with a single bomb from an altitude of 1,500 ft (460 m), followed by another aeroplane that straddled four destroyers.

The second wave of eight aircraft, led by Lieutenant Commander J. D. Hale of No. 819 Squadron, was now approaching from a northerly direction toward the Mar Grande harbour, with two of the four bombers also carrying flares, the remaining five carrying torpedoes. Flares were dropped shortly before 00.00. Two aircraft aimed their torpedoes at Littorio, of which one hit. Despite having been hit twice by anti-aircraft fire, another aeroplane aimed a torpedo at Vittorio Veneto, but this torpedo missed. Another aeroplane struck the battleship Caio Duilio with a torpedo, blowing a large hole in her hull and flooding both of her forward magazines. The aeroplane flown by Lieutenant G. Bayley was shot down by anti-aircraft fire from the heavy cruiser Gorizia following the successful attack on Littorio, and was the only aeroplane of the second wave to be lost. The final aeroplane to arrive, 15 minutes behind the others, made an unsuccessful dive-bombing attack on one of the Italian cruisers despite heavy anti-aircraft fire, then returned to Illustrious, landing at 02.39.

Of the two aircraft shot down, the pilot and observer of the first, Williamson and Lieutenant N. J. Scarlett, were taken prisoner. The pilot and observer of the second aeroplane, Lieutenant G. Bayley and Lieutenant H. Slaughter, were both killed.

The Italian battleships had suffered significant damage: Conte di Cavour had a hole, measuring 39 by 25 ft (12 by 8 m), in her hull, and permission to ground her was withheld until it was too late, so her keel touched the bottom at a deeper depth than intended. Some 27 of the ship’s crew had been killed and more than 100 others wounded. Only her superstructure and main armament remained above water, but the ship was subsequently raised, partially repaired and transferred to Trieste for further repairs and upgrades, though a changed situation meant that these works were accorded only a low priority. The ship was still undergoing repairs when Italy surrendered in September 1943, so she never returned to full service.

Caio Duilio had only a slightly smaller hole, measuring 36 by 23 ft (11 by 7 m), in her hull and was saved by being run aground.

Littorio had considerable flooding caused by three torpedo hits. Despite underwater protection (the 'Pugliese' system, standard in all Italian battleships), the damage was extensive, although real damage to the ship’s structures was relatively limited, and the machinery was intact. Her casualties were 32 men killed and many wounded. She was holed in three places, once on the port side measuring 23 ft by 4 ft 11 in (7 m by 1.5 m), and twice on the starboard side measuring 49 by 33 ft (15 by 10 m) and 39 by 30 ft (12 by 9 m). She too was saved by being run aground. Despite this, in the morning, the ship’s bows were totally submerged.

The Italian anti-aircraft defences fired 13,489 shells from the land batteries, while several thousand were fired from the ships. As noted above, only 4,600 yards (4200 m) of anti-torpedo net were actually fielded around the ships to a depth of 33 ft (10 m), while the need was 14,000 yards (12800 m). There were also 13 aerophonic stations and 22 searchlights (the ships had two searchlights each). Captain Denis Boyd, the commanding officer of Illustrious, stated in his after-action report that 'It is notable that the enemy did not use the searchlights at all during either of the attacks.'

Littorio was repaired with all available resources and was fully operational again within four months, while restoration of the older battleships proceeded at a much slower pace: the repairs took seven months for Caio Duilio, and the repairs for Conte di Cavour were never completed. In all, the Swordfish attack was made with just 20 aircraft. Two Italian aircraft were destroyed on the ground by the bombing, and two bombs hit the cruiser Trento and the destroyer Libeccio but failed to detonate. Near-misses damaged the destroyer Pessagno.

Meanwhile, the Force 'X' cruisers attacked an Italian convoy in the 'Battle of the Strait of Otranto'. Force 'X' was based on the light cruisers Ajax, Orion and Australian Sydney and the 'Tribal' class destroyers Nubian and Mohawk. Just after 00.00, Force 'X' met and destroyed four Italian merchant vessels (Capo Vado, Catalani, Locatelli and Premuda), damaged the torpedo boat Fabrizi, and forced the heavily outgunned auxiliary cruiser Ramb III to flee.

Cunningham and Lyster wished to attack Taranto once again on the following night with 15 Swordfish aircraft (six torpedo-bombers, seven bombers, and two carrying flares), but bad weather prevented the renewed action.

'Judgement' cost the Italian fleet half of its capital ships in one night. On the following day, the Regia Marina transferred its undamaged ships from Taranto to Naples to protect them from similar attacks, until Taranto’s defences (mainly the anti-torpedo nets) were brought up to levels adequate to provide protection from further attacks of the same kind: the defensive upgrade occupied the period between March and May. Cunningham wrote after the attack that 'The Taranto show has freed up our hands considerably & I hope now to shake these damned Eyeties up a bit. I don’t think their remaining three battleships will face us and if they do I’m quite prepared to take them on with only two.' Indeed, the balance of naval power had swung to the Mediterranean Fleet, which now benefitted from a greater degree of operational freedom: when previously forced to operate as a single formation to match the Italian strength in capital ships, the Mediterranean Fleet could now split into two battle groups, each centred on one aircraft carrier and two battleships.

Nevertheless, Cunningham’s estimate that the Italians would now be unwilling to risk their remaining heavy units was quickly proved to be wrong. Only five days after the 'Battle of Taranto', Campioni sortied with two battleships, six cruisers and 14 destroyers to disrupt a mission to deliver aircraft to Malta. The follow-up to this operation led to the 'Battle of Cape Spartivento' on 27 November 1940. Two of the three damaged Italian battleships had been repaired by the middle of 1941, and thereafter control of the Mediterranean continued to swing back and forth until the Italian surrender,

The British attack on Taranto was avenged a year later by the Italian navy in its raid on Alexandria, when the Mediterranean Fleet was attacked by manned torpedoes, which severely damaged the battleships Queen Elizabeth and Valiant.

However, measured against its primary task of disrupting Axis reinforcement and supply convoys to North Africa, the 'Battle of Taranto' had little effect. In fact, Italian shipping to Libya increased between October 1940 and January 1941 to an average of 49,435 tons per month, up from the 37,204-ton average of the previous four months. Moreover, rather than change the balance of power in the central Mediterranean, the British had 'failed to deliver the true knockout blow that would have changed the context within which the rest of the war in the Mediterranean was fought'.

Air-launched torpedo experts in all modern navies had previously thought that torpedo attacks against ships must be in water at least 75 ft (23 m) deep. Taranto harbour had a depth of only about 39 ft (12 m); but the Royal Navy had developed a new method of preventing torpedoes from diving too deep after entering the water. Beneath the nose of the launcher aeroplane, a drum was fitted from which a roll of wire led to the nose of the torpedo. As it dropped, the tension from the wire pulled up the nose of the torpedo, producing a belly-flop rather than a nose dive.

It is likely the Imperial Japanese navy’s staff carefully studied the 'Battle of Taranto' during the planning for the 'Ai' carrierborne air attack on the US Pacific Fleet in Pearl Harbor as both attacks faced similar issues in attacking in shallow water. The Japanese assistant naval attaché to Berlin, Lieutenant Commander Takeshi Naito, flew to Taranto for a first-hand investigation of the attack, and in October 1941 had a lengthy conversation about his observations with Commander Mitsuo Fuchida, who was to lead the Japanese attack on 7 December 1941. More significant, perhaps, was a Japanese military mission to Italy in May 1941. A group of Japanese officers visited Taranto and had lengthy discussions with their Italian naval counterparts. However, the Japanese had been working on shallow-water torpedo solutions since a time early in 1939, with various shallow ports, including Manila, Singapore, Vladivostok and Pearl Harbor, as the notional targets. Early in the 1930s, as their 18-in (450-mm) Type 91 aerial torpedo entered service, the Japanese used a breakaway wooden nose to soften its impact with the water, and as early as 1936 they had perfected breakaway wooden fins for added aerial stability.

The Japanese attack on Pearl Harbor was a considerably larger operation than the British attack on Taranto. All six of the Imperial Japanese navy’s fleet carriers, each equipped with an air wing having over twice the number of aircraft as any British carrier, were involved. 'Ai' thus resulted in far more devastation: seven US battleships were sunk or disabled, and several other warships were destroyed or damaged. The US Navy thereafter centred its fleet operations in the Pacific Ocean around its carriers instead of its battleships as the capital ships. Battleships were found to be less useful in the expanses of the Pacific Ocean than in the confines of the Mediterranean Sea and, moreover, the older US battleships were too slow to escort the carriers and were employed chiefly as fire support units for amphibious operations.