In the 1930s Lucas was widely known for his political letters to the British Press with their outspoken attacks on the policy that came to be known as appeasement. Following the inaction of the League over Manchuria, he called repeatedly for "a League within the League", of nations pledged to uphold international law and oppose aggression. "Since the War," he wrote in 1933, "British policy has been shuffling, timid, ignoble." Having read "Mein Kampf" in the unexpurgated original and taken its threats as a statement of intent, he urged in September 1933 that Nazi Germany be prevented from re-arming. "Versailles was monstrous", he wrote in "The Week-end Review",