The German heavy cruiser Admiral Graf Spee had cruised into the South Atlantic a fortnight before the war began, and had been commerce raiding after receiving appropriate authorization on 26 September 1939.
One of the hunting groups sent by the British Admiralty to search for Admiral Graf Spee, comprising three Royal Navy cruisers, HMS Exeter, Ajax and Achilles, found and engaged their quarry off the estuary of the River Plate close to the coast of Uruguay in South America.
In the ensuing battle, Exeter was severely damaged and forced to retire; Ajax and Achilles suffered moderate damage. The damage to Admiral Graf Spee, although not extensive, was critical her fuel system was crippled. Ajax and Achilles shadowed the German ship until she entered the port of Montevideo, the capital city of neutral Uruguay, to effect urgent repairs. After Admiral Graf Spee’s captain Hans Langsdorff was told that his stay could not be extended beyond 72 hours, he scuttled his damaged ship rather than face the overwhelmingly superior force that the British had led him to believe was awaiting his departure.