After World War II in Europe began, Dietrich led the "Leibstandarte" during the German advance into Poland and later the Netherlands. After the Dutch surrender, the "Leibstandarte" moved south to France on 24 May 1940. They took up a position 15 miles southwest of Dunkirk along the line of the Aa Canal, facing the Allied defensive line near Watten. That night the OKW ordered the advance to halt, with the British Expeditionary Force trapped. The "Leibstandarte" paused for the night. However, on the following day, in defiance of Hitler's orders, Dietrich ordered his III Battalion to cross the canal and take the heights beyond, where British artillery observers were putting the regiment at risk. They assaulted the heights and drove the observers off. Instead of being censured for his act of defiance, Dietrich was awarded the Knight's Cross of the Iron Cross. During this campaign members of the "Leibstandarte" 2nd Battalion were responsible for the murder of 80 British and French POWs, in what became known as the Wormhoudt massacre.