While serving with the Bushveldt Carbineers during the Second Anglo-Boer War, Lieutenant Morant was arrested and court-martialled for war crimes—one of the first such prosecutions in British military history. According to military prosecutors, Morant retaliated for the death in combat of his commanding officer with a series of revenge killings against both Boer POWs and many civilian residents of the Northern Transvaal. Morant's defence attorney, Major James Francis Thomas, demanded the acquittal of his clients under what is now called the Nuremberg Defence, alleging that his clients could not be held legally or morally responsible, because they only followed orders.