Very slightly off course, near Obrestad, on the south-western cape of Norway, she was hit by friendly fire seven days after the start of World War II costing 53 lives and leaving two survivors.

[2] After commissioning, Oxley and Otway were temporarily assigned to the Royal Navy's 5th Submarine Flotilla.

[3] Oxley underwent diving exercises every second week until 9 April 1931,[3] when the submarine was paid off in full prior to transfer to the RN.

[3] The ongoing cost of maintaining the boats, coupled with the tonnage limits imposed by the London Naval Treaty prompted the Australian government to offer Oxley and Otway to the Royal Navy.

[4] Following the outbreak of the Second World War, Oxley was assigned to patrol duties off the coast of Norway.

[2] When the Admiralty was notified that British Government would declare war on Germany, five submarines of the Second Flotilla, including HMS Triton and HMS Oxley, were ordered to patrol on the Obrestad line off Norway on 24 August 1939.

At 19:55 on 10 September 1939, Triton had surfaced, fixed a position off the Obrestad Light, set a slow zigzag patrol, and began charging batteries.

Lieutenant Commander Steel, having verified that the area was clear and having posted lookouts, gave the bridge to the officer of the watch and went below, leaving orders that he was to be called if anything unusual appeared.

Steel ordered propulsion shifted to the main motors, the signalman to the bridge, and torpedo tubes 7 and 8 readied for firing.

The light from the Aldis lamp revealed three men floundering amid oil and debris.

Oxley was out of position, Triton had acted correctly, and the first Allied submarine casualty of World War II was due to "friendly fire."