attack on the Altmark was set out in a Note to the Norwegian Government from Foreign Secretary Lord Halifax dated 10 March 1940. The problem the British Government faced was the wording of The Hague Convention XIII of 1907 to which it was a signatory. Article 10 provides that: "The neutrality of a Power is not affected by the mere passage through its territorial waters of warships or prizes belonging to belligerents." This meant that the Altmark was within its rights to sail through Norwegian waters with prisoners aboard providing that it did not come to a protracted stop longer than 24 hours. In the diplomatic letter, the British government confirmed that it was not contrary to the law of neutrality to sail a prison ship through neutral waters, and Britain often did this herself. In fact the British complaint had nothing to do with the prisoners. Altmark was a fleet tanker assimilated to a warship and was proceeding to Germany from the Atlantic by the north-about route. Instead of sailing down the North Sea as he would do in peacetime, the master of the Altmark had elected to sail the entire leg of the voyage southwards within Norwegian territorial waters in order to attract immunity from attack there under international law. There was no other reason for him to want to voyage through waters so dangerous to navigation. With no valid breach of international law, the British excused their violation of international law by contriving that the Altmark's course abused international law even without a violation, and since the Norwegians had declined to stop a voyage that was not in violation of international convention the British Admiralty decided it was justified in taking action contrary to law, essentially announcing that it had the right to determine what course an enemy ship must travel to be entitled to the protections of international law. The question remains unresolved to this day as to whether, as the Hague Conventions stood in 1940, a warship could legitimately seek immunity from attack in neutral waters by widely varying its course to reach them. Subsequent history The ship, renamed Uckermark on 6 August 1940, then resumed the role for which she had been built. During Operation Berlin, which involved the battleships and between January and March 1941, Uckermark, under Captain Zatorski, was a supply ship and scout attached to the squadron. As the result of