This was a British carrierborne air attack by Admiral Sir James Somerville’s Eastern Fleet on targets on the island of Sumatra in the Netherlands East Indies and Sabang in Malaya within Japanese-occupied South-East Asia (25 July 1944).
On 19 June Vice Admiral Sir Arthur Power, Somerville’s second in command, had sailed from Trincomalee in Ceylon to carry out an attack on Port Blair in the Andaman islands group, but the weather was indifferent and the carrierborne aircraft launched by the fleet carrier Illustrious achieved little.
Early in the following month, by which time the Eastern Fleet had been boosted by the arrival of the fleet carriers Victorious and Indomitable, a larger-scale undertaking was planned and on 22 July Somerville led Victorious and Illustrious, three battleships, seven cruisers and 10 destroyers in an operation to bombard Sabang island off the northern tip of Sumatra.
At dawn on 25 July the British carrierborne warplanes attacked the nearby airfields, but were denied any significant target opportunities. Then the capital ships opened fire on the harbour and shore installations, and the cruisers and destroyers moved closer inshore to engage batteries and radar stations. The Dutch light cruiser Tromp and two British destroyers swept round the outer bay, engaging shore targets at point-blank range, and the destroyers fired torpedoes into the harbour as they passed its entrance. The air and surface ship attacks inflicted considerable damage on the oil tanks and repair shops of the port, and two small vessels totalling 1,500 tons were sunk.
No Allied ship suffered more than superficial damage from the Japanese return fire, and the carrierborne fighters were more than a match for the few Japanese aircraft which attempted to attack the ships of the Eastern Fleet as they pulled back.