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William Joyce pictured it so clearly: Winston Churchill being led to his hanging in a prison yard. “The Governor of a British prison accompanies Mr. Churchill on that last cheerless walk on a cold grey morning just before eight,” Joyce wrote in 1940. On his way to the gallows, Joyce added, Churchill should be reminded of the famine he brought upon England by inviting war with Germany, leaving the island’s lifelines snapped by German U-boats.

As it came to pass, England did not starve, and it was William Joyce who was led to the execution chamber of Wandsworth Prison one January morning in 1946. Convicted of aiding Nazi Germany as its chief propaganda broadcaster to Britain, he was the last person executed for treason in the U.K.

Born in Brooklyn to Irish immigrants, 40 years before, he returned with his parents to Galway at age 3. He never fit in there, being stridently pro-British in an Ireland on the verge of rebelling against British mastery. When the Irish War of Independence erupted in 1919, he fought as a young teenager with the Black and Tans—hastily mustered WWI veterans infamous for their brutality—against his fellow Irishmen. With the Black and Tans, a Security Service agent reported, Joyce “saw battle, murder, and sudden death at a very tender age.”

The Joyce family left for London upon the creation of the Irish Free State in 1922, fearing reprisal. It was there, as a university student, that Joyce discovered fascism, embracing it with an intensity few ever matched. Mussolini had been in power in Italy for a short time, his movement promising to many an alternative to the shortcomings of democracy, a boost to prosperity, and a bulwark against socialism. The Italian Blackshirts’ violence and strike-breaking spoke to Joyce’s inborn taste for militancy, order, and domination. And their anti-leftism appealed, since Joyce imagined a global Jewish Bolshevik conspiracy.

Joyce enlisted in Oswald Mosley’s British Union of Fascists as director of propaganda when the party became the leading standard-bearer for fascism in the U.K. in the early 1930s. He thrived, with a fellow fascist observing that Joyce was “a brilliant writer, speaker and exponent of policy … [who] addressed hundreds of meetings, always at his best, always revealing the iron spirit of fascism.” The BUF itself had around 40,000 members in 1934 and a number of wealthy and influential supporters, including press magnate Lord Rothermere, owner of the Daily Mail, and an array of dukes, marquesses, and baronets.

When Hitler came on the scene, Joyce found his true idol. The German added to Mussolini’s fascism an anti-Semitism that was central to Hitler’s and Joyce’s universal theory of how the world worked. Hitler articulated a vision of ending an imagined ages-long struggle between left and right, liberalism and absolutism, that appealed to Joyce, who also thought historically and saw the growth of fascism as the harbinger of the end of history. Joyce had spent his young life in search of the most totalizing ideas, the most uncompromising leader, and here they were.

Joyce lost his position with the British Union of Fascists in 1937 as the party itself lost support and clout as a result of its street violence and brawling at its rallies. Despite this, and the looming war with Germany, the diehard Joyce started an explicitly Nazi party in Britain, deriding Mosley as a vain pretender and the BUF as insufficiently hardcore.

A few months before the outbreak of war, MI5 reported of Joyce:

He has identified himself unreservedly with the Nazi cause, maintains close contact with Nazi officials and has shown that he would be quite willing to take action inimical to this country in order to further the campaign against the supposed “world Jewish conspiracy.” …He has on several occasions shown that he favours violent methods and through his whole career has shown himself to be a man of unbridled fanaticism.

The MI5 report concluded by suggesting he be detained when war broke out. But, possibly tipped off, Joyce and his wife—a fellow fascist—fled for Berlin only days before Britain declared war in September 1939. Joyce, a U.S. citizen, falsely claimed U.K. citizenship on his passport application.

Within only weeks, Joyce had a job in the German Propaganda Ministry’s English-language broadcasting section. Radio broadcasting had exploded over the course of the decade, with affordable receivers becoming ubiquitous and commercial broadcasters crowding the airwaves. Quickly, people came to view radio as an entertainment essential and information lifeline.

As such a lifeline, radio was never more vital than in wartime for the British public. The state-monopoly BBC, though, was heavily censored and played a somnolent organ refrain at intervals throughout the day. This made English-language radio beamed from the continent an appealing alternative.

Beginning his broadcasts with the catchphrase, “Germany calling, Germany calling,” Joyce would read genuine news gleaned from papers acquired in neutral countries, mixed with exaggerations about overwhelming German victories—though the real victories in the early months of the war were significant enough. Then Joyce would offer what he called “views on the news”—his editorial perspective.

This is when he would let loose on “the aged satyr” Churchill, for example, “the whiskey-guzzling, cigar-chomping, bovine decadent liar.” Or he would recycle some of his pro-Nazi speeches from earlier days in the BUF. In 1940 and early 1941, with German victories mounting and the British with little to celebrate, Joyce was in his heyday.

In his private life, Joyce was a domestic abuser, assaulting his first and second wives repeatedly; his broadcasts to Britain fit this pattern of torment and intimidation. Germany, he declared, wanted peace, but the British had forced the Reich into violence. Germany did not want to bomb the women and children of Britain, but it had been left no choice. Ultimately, though, a harsh corrective would be for Britain’s own good.

Joyce did not try to charm or coax. He created a sense that Germany could come and overrun Britain at any moment of Hitler’s choosing. The only thing that could save the British people from ruin was if they tore down Churchill and came to terms. Since Joyce genuinely seemed to believe that a Jewish conspiracy pulled the strings controlling the British state, there can be little doubt that he imagined a final reckoning for them in the future.

Within Britain, Joyce received a mixed response. The newspapers tried to make him an object of ridicule, making fun of his pompous accent. “He speaks English of the haw, haw, damit-get-out-of-the-way variety, and his strong suit is gentlemanly indignation,” wrote one columnist. And from then on, Joyce was known as “Lord Haw-Haw,” a staple of cartoons and jokes.

But the public, hungry for alternative channels of news, sought him out. The British Ministry of Information estimated that he had 6 million regular and 18 million occasional listeners. (Twenty-three million people regularly listened to the BBC.) Still, people recalled finding his voice “horrible” and “creepy.” Some thought his broadcasts contained messages for German agents or predicted where the next bombs would fall. They were not laughing.

The problem for Joyce was that the tactic of guaranteeing Britain’s ruin if its people did not rise against Churchill became less and less effective from around early 1942. Britain held out against the Blitz, the Royal Air Force made the Channel impassable, and then the Soviets and U.S. were drafted into the war effort.

Joyce was loyal to Hitler and the cause until the last. He and his wife ran ahead of the invading Soviet and U.S. armies, broadcasting until the last possible moment in May 1945. They were both captured alive and returned to the U.K.

The government put William Joyce on trial for treason, even though he was not really a British subject. In his claim for a British passport, went the government’s case, he had claimed the protection of the crown and was thus bound to loyalty. Legal experts still consider this a dubious line of reasoning. The fact is that the British state intended to have its lethal revenge against a figure it detested.

In his last letter to his wife before his execution by hanging, William Joyce expressed the hope that, “once again … may the Swastika be raised from the dust, crowned with the historic words ‘You have conquered nevertheless.’ ” Then he took his last cheerless walk.