'Breach' was a British naval undertaking to deny the Italians the effective use of the harbour of Mogadishu, the capital of Italian Somaliland (2 February 1941).

The operation was undertaken by aircraft of the fleet carrier Formidable, then on passage round Africa to join Admiral Sir Andrew Cunningham’s Mediterranean Fleet in Alexandria, supported by the heavy cruiser Hawkins. The two ships were also searching for the German merchant raider Atlantis (Schiff 6 and HSK-2, also known to the British as Raider C). Formidable's aircraft mined the approaches to Mogadishu harbour and attacked the shipping and installations in the harbour, and then nine Fairey Albacore single-engined bombers struck at sundry shore and harbour installations.

At the same time the heavy cruiser Shropshire and light cruisers Ceres and Colombo blockaded Kismayu, farther to the south-west and close to the border with Kenya.