page_title: Battle of Madagascar
section_title: Naval Forces
hierarchical_section_title: Battle of Madagascar / Order of battle / Vichy France / Naval Forces
caption_attribution_description: English: Japanese submarine I-10 (A-class), at Penang Port. 日本語: 日本海軍潜水艦「伊号第10潜水艦」（甲型）ペナン港を出港中
context_page_description: The Battle of Madagascar was the British campaign to capture the Vichy French-controlled island Madagascar during World War II. The seizure of the island by the British was to deny Madagascar's ports to the Imperial Japanese Navy and to prevent the loss or impairment of the Allied shipping routes to India, Australia and Southeast Asia. It began with Operation Ironclad, the seizure of the port of Diego-Suarez near the northern tip of the island, on 5 May 1942.
  A subsequent campaign to secure the entire island, Operation Stream Line Jane, was opened on 10 September. The Allies broke into the interior linking up with forces on the coast and secured the island by the end of October. Fighting ceased and an armistice was granted on 6 November. This was the first large-scale operation by the Allies of World War II combining sea, land and air forces. Historian John Grehan has claimed that the British seizure of Madagascar before it could fall into Japanese hands was so crucial in the context of the war that it lead to Japan's eventual downfall and defeat.
context_section_description: Merchant Cruiser Bougainville 2
  Sloop D'Entrecasteaux
  Submarines
  Bévéziers
  Héros
  Monge
caption: Japanese submarine I-10 in Penang, 1942.
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