In 1940, British forces began battling the Italians in North Africa. While the Italians were easily able to supply their troops, the logistical situation for the British proved more difficult as their ships had to traverse almost the entire Mediterranean. Early in the campaign, the British were able to control the sea lanes, however by mid-1940 the tables were beginning to turn, with the Italians outnumbering them in every class of ship except aircraft carriers. Though they possessed superior strength, the Italians were unwilling to fight, preferring to follow a strategy of preserving a "fleet in being."
Concerned that Italian naval strength be reduced before the Germans could aid their ally, Prime Minister Winston Churchill issued orders that action be taken on the issue. Planning for this type of eventuality had begun as early as 1938, during the Munich Crisis, when Royal Navy leaders first conceived an operation calling for an aerial attack on the Italian fleet base at Taranto. This plan was reactivated in September 1940, when its principal author, Rear Admiral Lumley Lyster, joined Admiral Sir Andrew Cunningham's Mediterranean fleet with the new carrier HMS Illustrious.
Codenamed Operation Judgment, Cunningham and Lyster planned to attack Taranto on October 21, Trafalgar Day, with aircraft from HMS Illustrious and HMS Eagle. This was later changed following fire damage to Illustrious and action damage to Eagle. While Eagle was being repaired, it was decided to press on with the attack using only Illustrious. Several of Eagle's aircraft were transferred to augment Illustrious' air group and the carrier sailed on November 6. In the days before the attack, several reconnaissance flights from Malta confirmed that the Italian fleet was at Taranto