Altmark exposed the limits of Norwegian neutrality

Norwegian leaders continued to approach neutrality violations as disputes that negotiation could resolve, even when the belligerents would not abandon their objectives. During the Altmark incident on 16 February 1940, Germany carried British merchant sailors as prisoners through Norwegian waters, and British forces entered the fjord and fought to release them. The German violation became visible through the British intervention. In this interpretation, Altmark's successful return to Germany might have prompted a British invasion of Norway in March by demonstrating that Norway could not enforce its neutrality. British officers respected their Norwegian counterparts, but distrusted a government that had withheld the forces and equipment needed to police the coast.