British oxygen-enriched 21-inch torpedoes

Did British and Australian forces use oxygen-powered 21-inch torpedoes?

British service included oxygen-enriched-air types, notably the Mark VII and its Mark IX development, alongside other propulsion systems.

Wartime British torpedoes did not form one uniform weapon family. Several generations and propulsion arrangements remained in service at the same time because different cruisers and destroyers retained different launchers and weapon fits. Wet-heater and burner-cycle weapons differed from the oxygen-enriched-air Mark VII used by County-class cruisers. The Mark IX fitted to Leander-class cruisers was a development related to that oxygen-enriched design. The Australian question therefore points toward British-family Marks VII or IX rather than implying that every 21-inch torpedo used pure oxygen or the same engine system.