In an attempt to solidify the gains made in Burma, and to weaken Allied resupply capabilities in the case of a push-back, Japan launched a naval offensive in the Indian Ocean centred on Ceylon. The fleet, led by Admiral Nagumo, began its foray into the Indian Ocean by moving north to launch a large aerial attack the port of Colombo. Japanese planes spotted Dorsetshire and Cornwall on their way to join the rest of the British forces in the southwest, and sunk both. At the same time raids against shipping were made by a smaller Japanese fleet under Admiral Ozawa in the East. Nagumo’s fleet then sailed east to attack Trincomalee and ran into the light carrier Hermes which, without any aircraft aboard, was easily sunk. The majority of the British fleet was spared contact with the Japanese during the raid due to navigation and intelligence errors on both sides.
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