Gunboat diplomacy through the Altmark incident

James Cable introduces limited naval force through Norway's handling of Altmark in February 1940. An initial investigation accepted the tanker as a merchant vessel, but Admiral Tank-Nielsen found that the prescribed inspection questions had not been answered satisfactorily. He had already circulated a newspaper warning that Altmark might bring 400 British prisoners across the Atlantic, but that warning had failed to reach the investigating torpedo-boat commanders. His chief of staff subsequently observed SOS signals and attempts by Altmark's crew to conceal them. The captain refused a search on the grounds that Altmark was a state ship. Tank-Nielsen responded by refusing passage through the defended area, avoiding an immediate confrontation over the right to search. Higher authority then allowed Altmark to pass as a state ship, hoping to move it onward before British detection created a crisis. Intelligence failures and disagreements within the Norwegian command therefore shaped how neutrality was enforced.