'MD1' was a British naval undertaking to lay mines and attack Italian shipping in Benghazi harbour (17 September 1940).

The task was undertaken by aircraft from the fleet carrier Illustrious of Admiral Sir Andrew Cunningham’s Mediterranean Fleet, and was designed to impede the flow of equipment and fuel to the Italian forces in the Western Desert. The Italian destroyer Borea was sunk during the undertaking, and the minefield laid at this time later sank the Italian destroyer Aquilone and two supply ships.