The commander, Admiral Philip Vian, had his flag aboard the aircraft carrier HMS Indomitable (carrying 857, 1839 and 1844 Naval Air Squadrons).

Also in Force 67 were the carrier Illustrious (carrying 854, 1830 and 1833 Naval Air Squadrons), the cruisers Argonaut, Black Prince and Newcastle, and the destroyers Kempenfelt, Wakeful, Wessex, Whirlwind and Wrangler.

Undetected, the fleet reached the flying-off position, north of Diamond Point, in the early morning of 20 December.

[1] At the flying-off position, low clouds and heavy squalls reduced visibility, prompting Vian to postpone the launch twenty minutes.

Strike Leader Stuart advanced through a gap in the clouds to inspect the target but was unable to locate it.

[1] The Avengers bombed the wharves from 1500 feet, while the Corsairs strafed the fuel storage tanks and warehouses in the town.

The defences of Belawan Deli were unprepared: the anti-aircraft artillery was ineffective and no fighters were put in the air, although one Mitsubishi Ki-21 was surprised and downed by a Hellcat.

At the suggestion of Captain C. E. Lambe of Illustrious, eight of his Corsairs and eight Hellcats from Indomitable were dispatched for a low-level sweep over the airfields at Sabang and Oleelhoe, the port of Kota Raja.