Torpedo testing behind Narvik reliability

Why did British torpedoes perform better at Narvik than German torpedoes?

A much larger and more routine test-firing programme gave the Royal Navy more chances to find faults before combat, despite continuing imperfections.

British torpedo reliability benefited from the scale of a global navy that repeatedly tested launch gear, crews, and weapons. Ships, destroyers, and submarines conducted routine firings around the world, creating feedback that a smaller programme could not easily match. The Royal Navy's post-Jutland concern with weapon testing reinforced that practice. British torpedoes still had faults early in the Second World War. Given the amount of testing, those surviving defects are harder to excuse.