War Order No. 154
War Order No. 154 was issued during World War II at the end of November or the beginning of December 1939. It was the first explicit instruction by the German Navy (German: Kriegsmarine) to use the tactics of unrestricted submarine warfare.
The order was as follows:
- [last paragraph] Do not rescue any men; do not take them along; and do not take care of any boats of the ship. Weather conditions and proximity of land are of no consequence. Concern yourself only with the safety of your own boat and with efforts to achieve additional successes as soon as possible. We must be hard in this war. The enemy started the war in order to destroy us, and thus nothing else matters.
The German Navy started World War II with Prize Rules which complied with Article 22 of the First London Naval Treaty. The Third Reich was indirectly bound to the Second London Naval Treaty of 1936 by the 1935 Anglo-German Naval Agreement and the Second London Naval Treaty affirmed that Article 22 of the 1930 treaty remained in force, and that "all other Powers [were invited] to express their assent to the rules embodied in this Article."
In general, Article 22 stated that merchant vessels which did not demonstrate "persistent refusal to stop" or "active resistance" could not be sunk without the ship's crew and passengers being first delivered to a "place of safety." The ship's lifeboats were not a place of safety, unless other shipping or land was close at hand.
On the very first day of the war, SS Athenia was sunk by U-boat U-30. Mistaking the Athenia for an "armed merchantman," no opportunity was provided to the ship's crew or passengers to be first delivered to a "place of safety."
However, in the weeks that followed, as was laid out in the transcript of Dönitz's Nuremberg Trial,  both the British and the Germans issued orders to their respective fleets which quickly made any initial compliance with Article 22 less and less possible.
War Order No. 154, along with the "Laconia Order" of 1942, were introduced by the prosecution at the post-war Nuremberg Trial of Grand Admiral Karl Dönitz. In the judgment it was found that by issuing these two orders, he caused Germany to be in breach of the Second London Naval Treaty of 1936. However, as evidence of similar conduct by the Allies was presented at his trial, his sentence was not assessed on the grounds of this breach of international law. 
- Exhibit Number GB-196 Trials of German Major War Criminals: Volume 13 Thursday, 9 May 1946, Day 125 the Avalon Project at the Yale Law School
- Treaty for the Limitation and Reduction of Naval Armaments, (Part IV, Art. 22, relating to submarine warfare). London, 22 April 1930
- Procès-verbal relating to the Rules of Submarine Warfare set forth in Part IV of the Treaty of London of 22 April 1930. London, 6 November 1936
- Natalino Ronzitti (1988). "The Law of Naval Warfare: A Collection of Agreements and Documents with Commentaries", Martinus Nijhoff, ISBN 90-247-3652-8. p. 357
- Trials of German Major War Criminals: Volume 13 Saturday, 11 May 1946, Day 127 Monday, Monday, 13 May 1946, Day 128 the Avalon Project at the Yale Law School
- Judgement : Doenitz the Avalon Project at the Yale Law School