It is easy to get swept away with the importance of the event, because of our involvement. But it was not a decisive battle. The loss of a single German ship was never going to critically alter the fortunes of World War Two. On the other hand, the scuttling of the "pocket battleship" the Admiral Graf Spee provided a much needed propaganda boost for the Allies.
The Admiral Graf Spee was at sea when World War Two began. She spent a couple of months in the Atlantic searching for British merchant vessels, and she sank several. The Royal Navy assembled a number of warships to hunt for the German ship, and on 13 December 1939 a British cruiser force located her.
The engagement in the South Atlantic between the Admiral Graf Spee, and three Allied cruisers (the British heavy cruiser Exeter, the British light cruiser Ajax and the New Zealand light cruiser Achilles) was tactically a draw, but the lighter British ships took more of a beating. Exeter was left crippled and was knocked out of the battle. Had the Germans not lost their nerve and run to a neutral port, Montevideo, the battle would probably have been a major defeat for the Allies, and our own Achilles may well have ended up on the bottom of the South Atlantic.
A chart showing the action on 13 December
The decision by the German captain Hans Langsdorff to scuttle his ship still baffles historians. It appears he grew convinced that an overwhelming Allied naval force was waiting outside Montevideo harbour. In fact, the only Allied ships on hand were the two light cruisers Ajax and Achilles, and the heavy cruiser Cumberland. Had the Graf Spee gone out to fight she may well have fought her way to safety.
International law meant that the Graf Spee had to either leave Montevideo by 17 December, or face internment. So on 17 December the Graf Spee set sail, only to be scuttled on Langsdorff's orders. He did this because he believed the Germans were doomed, and he wanted no further loss of life - except for his own. He shot himself two days later.
The scuttling of the Admiral Graf Spee
It's also almost unique among the battles we remember from the World Wars , because it didn't involve huge numbers of New Zealand dead. The New Zealand casualties were light - only two dead out of 72 Allied losses.