Altmark Incident The " Altmark " Incident ( Norwegian : " Altmark " - affæren ) was a naval skirmish of World War II between the United Kingdom and Nazi Germany , which happened on 16 February 1940 . It took place in what were , at that time , neutral Norwegian waters . To date , it is the last major boarding action fought by the Royal Navy . Background . In February 1940 , the German tanker was returning to Germany with 299 British merchant sailors on board , prisoners of war who had been picked up from ships sunk by the pocket battleship . On its way from the southern Atlantic to Germany , " Altmark " passed through Norwegian waters . On the insistence of British contacts who had been pursuing the vessel , it was investigated three times on 15 February by the Royal Norwegian Navy . First , the tanker was boarded by officers from the torpedo boat HNoMS " Trygg " off Linesøy Island , then by officers from the torpedo boat HNoMS " Snøgg " in the Sognefjord , and finally personally by Admiral Carsten Tank - Nielsen and naval personnel from the destroyer HNoMS " Garm " in the Hjeltefjord . In each instance , the men who boarded the ship carried out cursory searches and took the Germans ' word that the vessel was conducting purely commercial business . Following the third boarding , " Altmark " was escorted southwards by the torpedo boats HNoMS " Skarv " and HNoMS " Kjell " and the guard boat HNoMS " Firern " . The British prisoners held in the ship ' s hold reportedly made strenuous efforts to signal their presence , even though international law did not ban the transfer of prisoners of war through neutral waters . The Norwegian search parties however did not inspect the hold , and allowed the ship to continue on its way . Interception and boarding . " Altmark " was then spotted off Egersund later the same day by British aircraft , which raised the alarm in the Royal Navy . The aircraft were stationed at RAF Thornaby , in the North East of England . After being intercepted by the destroyer , captained by Philip Vian , " Altmark " sought refuge in the Jøssingfjord , but " Cossack " followed her in the next day . The " Altmark " ' s Norwegian naval escorts blocked initial attempts to board the ship , and aimed their torpedo tubes at the " Cossack " . Captain Vian then asked the Admiralty for instructions , and received the following orders directly from the then First Lord of the Admiralty Winston Churchill : The Norwegian forces refused to take part in a joint escort reiterating that their earlier searches of " Altmark " had found nothing . Vian then stated that he intended to board " Altmark " and invited the Norwegians to take part , but this was also refused . In the ensuing action , " Altmark " ran aground . The British then boarded her at 22 : 20 on 16 February , and — after some hand - to - hand fighting with bayonets and the last recorded Royal Naval action with cutlass — overwhelmed the ship ' s crew and then went down to the hold . One of the released prisoners stated that the first they knew of the operation was when they heard the shout " Any Englishmen here ? " from the boarding party . When the prisoners shouted back " Yes ! We are all British ! " , the response was " Well , the Navy ' s here ! " which brought cheers . Six German sailors were killed and eight wounded by the British , seven of whom were shot while trying to flee over the ice . This was used unsuccessfully as a defence by the Germans in the Nuremberg trials , as the British Commander rather than being tried himself , was decorated for the action . HMS " Cossack " left the Jøssingfjord just after midnight on 17 February . The Norwegian escorts protested , but did not intervene . The official explanation later given by the Norwegian government was that , according to international treaty , a neutral country was not obliged to resist a vastly superior force . Impact . The Norwegians were angered that their neutrality had been infringed , but they did not want to be dragged into a European war . Nonetheless , the " Altmark " incident sowed doubts about the Norwegian neutrality among the Allies , as well as in Germany . Both sides had contingency plans for military action against Norway , primarily to control the traffic of Swedish iron ore , on which the German armaments industry depended in the early stages of the war . The " Altmark " incident convinced Adolf Hitler that the Allies would not respect Norwegian neutrality , and on 19 February , he decided to intensify the planning for Operation " Weserübung " , the occupation of Denmark and Norway , which eventually took place on 9 April 1940 . The " Altmark " incident gave the British a short - lived but sorely needed morale boost during the Phoney War . The incident also had a lasting propaganda effect in German - occupied Norway during the war , when the Norwegian collaborationist government tried to neutralize their nickname " " Quisling s " " by using the location of the skirmish , Jøssingfjord , to coin the derogatory term " " jøssing " " , referring to pro - Allies and anti - Nazis . Their efforts backfired , as " " jøssing " " was immediately adopted as a positive term by the general public , and the word was banned from official use by 1943 . The phrase " The Navy ' s here " became well - known , being used as the title of a book about the incident published shortly after ; the publisher referred to " the simple statement which stirred the imagination of the world " . A popular song was written by Ross Parker and Hugh Charles which saluted the incident by comparing it with those of Drake , Nelson , Beatty , and Fisher .