The original intention of the authorities was to try Joyce for treason immediately, but when his complicated nationality issues came to light, the court case was forced back until September.

It was not clear that an individual, born in the United States, raised in Ireland, who obtained British citizenship via deception for a relatively short period, and who then obtained naturalised German citizenship, could legally be tried for treason against the British Crown, by broadcasting propaganda in an area outside of the Crown’s legal jurisdiction. Clearly, if Joyce owed no allegiance to the Crown, he could not be tried for committing treason against it.

When the case went to trial, on 17 September 1945, Joyce was charged on three counts of high treason, namely that:

1. William Joyce, on 18 September 1939, and on numerous other days between 18 September 1939 and 29 May 1945 did aid and assist the enemies of the King by broadcasting to the King's subjects propaganda on behalf of the King's enemies.

2. William Joyce, on 26 September 1940, did aid and comfort the King's enemies by purporting to be naturalised as a German citizen.

3. William Joyce, on 18 September 1939 and on numerous other days between 18 September 1939 and 2 July 1940 did aid and assist the enemies of the King by broadcasting to the King's subjects propaganda on behalf of the King's enemies.

The case took three days to hear. In order to overcome the confusion surrounding his citizenship, the prosecution argued that the British passport, which Joyce had renewed immediately prior to his escape from Britain, and which was valid until 2 July 1940, entitled him to the protection afforded to all British passport holders, and that he therefore owed allegiance in return. Had he kept his US citizenship during his time in Britain, he could never have been prosecuted on treason charges in the UK.

The judge, Mr. Justice Tucker, accepted the point of law presented, but instructed the jury to find him not guilty on the first two counts, which extended to periods beyond the validity dates of his British passport, when he was recognised in law to have been a US citizen.

The jury returned a verdict of guilty on the single remaining count of high treason. Carrying a mandatory capital sentence, Mr. Justice Tucker had no choice but to sentence William Joyce to death by hanging.

Despite general public satisfaction that Joyce had been brought to justice, there was widespread unease that his death penalty was as severe a sentence as those meted out to major war criminals, like those responsible for the massacres carried out in concentration camps. He had never directly claimed a single life, regardless of how reprehensible his political views might be.

On 27 September 1945, Joyce's lawyers gave notice of appeal, on the grounds that the Judge had ruled incorrectly that he could be expected to owe allegiance to the Crown during his time in Germany. The appeal was heard on 30 October and dismissed on 7 November.

Due to the important questions of law involved in the case, the Attorney General granted permission for the Joyce case to be heard before the House of Lords; the highest British court, which occurred between 10 and 13 December. The Lords also dismissed the appeal, on a vote of 3 to 1, on 18 December 1945.

All routes of appeal now exhausted, Joyce went to his death unrepentant and defiant saying: “In death as in life, I defy the Jews who caused this last war, and I defy the powers of darkness which they represent” according to the BBC.

He was hanged at Wandsworth Prison at 9am on 3 January 1946, the last person in British history to be hanged for treason. Like all executed prisoners, he was buried in unconsecrated ground within the prison grounds.

The fate of Margaret Joyce, who had followed much the same path as her husband, in terms of treasonable actions, was markedly different to that of her husband.

There are two main theories about her treatment after their arrest in Flensburg, and her return to the UK: firstly, that the authorities felt that she had suffered enough through her husband’s trial, and that they had no appetite for a further trial, and secondly, that Joyce agreed to keep his connections to MI5 secret, in exchange for the freedom of Margaret. Certainly, as a British citizen, born and raised, a treason case against her could more easily have been made than against her husband, although she was not as well known a broadcaster as her husband had been.

For whatever reason, she was never charged, and was instead shipped out of Britain shortly after his execution, but was allowed to return back to the UK some years later. She died in Soho, reportedly from alcohol-related illness, in 1972.On 18 August 1976, William Joyce's remains were exhumed from their site within Wandsworth Prison and returned for burial to Ireland, where they were re-interred at the New Cemetery in Bohermore, County Galway.

On 28 May 1945, Joyce was captured by British forces near the German-Danish border, in the town of Flensburg. Apparently Joyce’s accent had raised suspicions, and when he went to retrieve his forged identification papers from his pocket, to prove he wasn’t Joyce, he was thought to be reaching for a pistol, and was shot in the leg by an interpreter attached to the British forces, named Lieutenant Perry.

After recovering for a fortnight in Lueneberg Military Hospital, Joyce was transported back to the U.K on 16 June 1945. His capture was seen as a significant coup for the authorities and, conveniently, the day before Joyce's arrival, the Treason Act 1945 had been granted Royal Assent by King George VI, enabling Joyce to be charged with three counts of high treason.

Joyce’s pre-war profile was sufficient to secure both him, and his wife, work as broadcasters for the Reichsrundfunks Foreign Service, the German equivalent of the BBC, based in Charlottenburg. The exact source of his sobriquet, ‘Lord Haw-Haw’, is not entirely clear, but most attribute it to Daily Express radio critic Jonah Barrington, who described a propaganda broadcaster as speaking “English of the haw-haw, damn-it-get-out-of-my-way variety, and his strong suit is gentlemanly indignation.”

Although the name was attributed to Joyce, the broadcast heard by Barrington was actually made by Norman Baillie-Stewart, a Sandhurst-educated officer whose voice sounded far more pompous than the American-Irish nasal twang of Joyce. As Joyce’s broadcasts gained in popularity the name stuck, and was soon exclusively associated with his broadcasts, with their signature cry of ‘Jairmany Calling! Jairmany Calling!’

At the height of his popularity, in the period up to the Battle of Britain, it was believed that up to 16 million British people tuned in to his Nazi propaganda broadcasts, an activity which, while not strictly illegal, was frowned upon by British authorities.

Joyce became the most important propaganda broadcaster in Germany at the time, and both he and his wife were granted naturalised German citizenship on 26 September 1940. With almost as many listeners as the BBC, he gained an almost mythical status: there were claims that he could forecast bomb targets, and that he knew intimate details about target sites: in reality, because of reporting restrictions placed on the BBC by the War Office, he could sometimes scoop the official stories by a few hours, releasing details before they could be broadcast officially, but this was the extent of his ability.

In contrast to his sinister broadcasts, his odd accent was a source of ridicule, and he was parodied by comedians, and even became the subject of some advertisements. But the joke soured with the onslaught of German bombing in Britain, and his popularity waned – though in Germany he remained as popular as ever, and in September 1944 he was awarded the Cross of War Merit First Class, by Hitler, for his broadcasting efforts.

His anti-Semitic stance never faltered, and he continued to blame the war on what he referred to as ‘Jewish International Finance’. He remained true to his belief that Germany and Britain needed to unite against the global Communist threat.In addition to broadcasting, Joyce's duties included distributing propaganda among British prisoners of war, whom he tried to recruit into the British Free Corps, a branch of the Waffen SS. He also wrote a book comparing National Socialist Germany to the evils of a Jewish-dominated capitalist Britain, called ‘Twilight over England’, that was promoted by the German Ministry of Propaganda.As the tide of war turned against Germany, Joyce began to drink heavily and his marriage soured. Both he and his wife, who took opium, in addition to also drinking heavily, became embroiled in numerous extramarital affairs.

In the final days of the war, with the Russian Army advancing inexorably towards Berlin, Joyce was forced to move to Hamburg to make his broadcasts, and his final transmission, during which he was clearly intoxicated, was made on 30 April 1945, in which he continued to rail against the Communist threat, and which he ended with a final, defiant ‘Heil Hitler!'

The following day Radio Hamburg was seized by advancing British forces, which made a final, mock "Germany Calling!" broadcast, denouncing Joyce, who had been forced to flee again, with his wife, this time north towards the Danish border.

Born: 24 April 1906

Arrested: 28 May 1945

Trial: 17 September 1945

Convicted: 19 September 1945

Died: 3 January 1946