It had become clear in the aftermath of the ‘Ironclad’ operation against Diégo Suarez that the Vichy French administration of Madagascar would not capitulate willingly to the British and commonwealth forces, and there thus remained the possibility of an intensification of the Japanese submarine offensive in the Mozambique Channel. Through this strategically important passage moved most of the convoys carrying British reinforcements and matériel to North Africa, the Middle East and India, and during June and July 1942 Japanese submarines had indeed operated in these waters, sinking 20 ships (94,000 tons) before withdrawing during the later part of July.

It was therefore essential that Madagascar (and especially its western coast ports of Majunga, Morondava and Tuléar) be brought into the Allied fold in an enlargement of the undertaking started by ‘Ironclad’. To this end ‘Stream’ secured Majunga when Brigadier F. W. Festing’s 29th Independent Brigade Group was landed there on 10 September with the support of Rear Admiral W. G. Tennant’s Force ‘A’ provided by Admiral Sir James Somerville’s Eastern Fleet and comprising the light cruisers Birmingham, Gambia and Free Dutch Jacob van Heemskerck, and destroyers Napier, Nepal, Nizam, Australian Norman, and Free Dutch Tjerk Hiddes and Van Galen of the 7th Destroyer Flotilla. Air cover for ‘Stream’ was provided by the fleet carrier Illustrious and seaplane tender Albatross, which were escorted by the destroyers Express, Fortune, Hotspur and Inconstant.

The 29th Independent Brigade Group was later re-embarked for the ‘Jane’ landing of 18 September, with the same naval supporting force, at Tamatave on the island’s eastern coast, its place being taken by Brigadier W. A. Dimoline’s 22nd (East Africa) Brigade Group for an advance inland toward the capital, Tananarive, which fell on 23 September. [5.en.http://codenames.info/operation/stream/]