The first Australian shot of the war took place several hours after the declaration of war when a gun at Fort Queenscliff fired across the bows of an Australian ship that failed to identify itself as it attempted to leave Melbourne without required clearances. On 10 October 1939, a Short Sunderland of No. 10 Squadron, based in England for re-equipment, became the first Australian and the first Commonwealth air-force unit to go into action when it undertook a mission to Tunisia.