The British Tanganyika expedition enjoys the reputation of being the smallest, most novel, and most distant naval enterprise undertaken during the great war. Rarely indeed have officers and men of the Royal Navy worked in an environment so foreign or met conditions of greater difficulty with more complete ultimate success.
The expedition, unique in British history, was made necessary by the military and naval situation in German East Africa in 1915. Although the German cruiser Königsberg had been destroyed in the Rufiji River early in July, some munitions were salved. These, together with supplies received from ships which evaded the somewhat ineffectual blockade of the cape squadron, not only enabled the resourceful German military forces in East Africa to continue a sturdy defense of their colony but made it seem possible for them to advance against Mombasa. Early in the war they had gained control of Lake Tanganyika, and the immense length of the lake served to shield the Germans from an attack based on Belgian Congo.