William Wallace

The Scot’s trial proved there was little to prevent kings from using treason laws to pursue vendettas

On 23 August 1305, William Wallace was convicted of treason at Westminster Hall in London. He then suffered the gruesome fate of the male traitor: hanging, drawing and quartering. King Edward I was determined to revenge himself brutally on this tiresome figurehead of Scottish independence – who had famously defeated English forces at Stirling Bridge in 1297 – and the Wallace case proved to be a watershed. It signified an extension by Edward I of the crime of treason, which now meant not just plotting the death of the king, but also the act of “levying war” (rebellion). In this way, England’s monarchs by the 14th century were defining “treason” arbitrarily to suit their own purposes.

In the 1350s the English barons finally acted to curb such royal behaviour. As part of a number of political concessions, they used Edward III’s request for money for his wars in France to leverage a special parliamentary law that would define treason more precisely. According to the 1351 Treason Act, treason above all meant a crime against the monarch. It occurred “when a man doth compass or imagine the death of our lord the king, of our lady his queen, or of their eldest son”. Here, to plot treason (compass or imagine) was the same as to carry out the deed. But it was also treason to “levy war against our lord the king in his realm”, or to aid the king’s enemies, “giving to them aid and comfort in the realm or elsewhere”.

This might sound like precise language, guaranteed to restrain royal tyranny. In fact it proved to be remarkably vague. And an extra clause in the 1351 act offered unscrupulous monarchs still further latitude. It stipulated that, if judges could not decide what was “treason”, they had to refer the case to king and parliament.

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Monarchs exploited this new clause to create “Acts of Attainder”, by which an individual was simply declared to be a “traitor” and found guilty of treason by act of parliament. In short, with parliament’s help, the king had became judge, jury and, in a number of cases, executioner.

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Thomas More

Words, not deeds, sent Thomas More to the block in 1535

Tudor England saw a sharp rise in cases of treason. The Tudor monarchs introduced 68 new treason laws in order to bolster the dynastic succession, but also to uphold the religious break with Rome. This process began in the 1530s with Henry VIII keen to strengthen his position after marrying Anne Boleyn. Henry saw the 1351 Treason Act as inadequate for punishing new types of traitor. In 1533, a nun named Elizabeth Barton prophesied that the king would die if he married Anne. Henry wanted Barton tried for treason, but his judges disagreed and finally an Act of Attainder was passed to convict and execute her.

However, it was Sir Thomas More who most famously fell foul of the Treasons Act of 1534, which pronounced it “treason” to abuse the king by calling him a heretic or tyrant through use of “malicious words”. More was a fierce opponent of the Reformation and, as lord chancellor, refused to take an oath acknowledging Henry as supreme head of the English church over the pope. It was a stance that would land More in the Tower of London.

It was while in the Tower that More received a visit from Richard Rich, the solicitor-general. Rich tried to trick the prisoner into confessing his treason, later claiming that More had denied Henry’s supremacy. Significantly, Rich and More were the only two present at the exchange. When More appeared in court in 1535, he refuted the idea that he had spoken “maliciously”, asserting that Rich was lying and adding: “I am more concerned for your perjury than my own danger.”

This did not save More. The jury took just 15 minutes to find him guilty of “treason by words” and he was beheaded. The case showed the dangerous potential of the 1534 Treasons Act. It was repealed after Henry’s death and, from then on, any charge of treason required two witnesses as proof.

Edmund Campion

In 1581, the Jesuit priest Edmund Campion denied that Catholicism equalled treason. The authorities disagreed

To some in the era of Elizabeth I, the Jesuit priest Edmund Campion was an evil Catholic “traitor”. It was under Elizabeth that Roman Catholics were increasingly seen as traitors within the state, for in 1570 the pope had excommunicated the queen as a Protestant heretic. This showed English Catholics that they no longer owed the queen any allegiance. It also spurred on Elizabeth’s government to create a raft of new treason laws to shore up her security.By the 1580s, treason law was veering in a sharply anti-Catholic direction due to an influx of Jesuit priests into the country. With the blessing of the pope, their mission was to lead England back to the Catholic faith.

Edmund Campion shown (right) with fellow Jesuit priest Robert Parsons. The authorities secured Campion’s conviction by portraying him as a common traitor.
Edmund Campion shown (right) with fellow Jesuit priest Robert Parsons. The authorities secured Campion’s conviction by portraying him as a common traitor. (Photo by Alamy) Alamy

In June 1580, Edmund Campion, disguised as an Irish jeweller, slipped secretly into England from France. For a year he said masses in Catholic houses around the country, but the authorities were in hot pursuit and finally he was arrested, discovered hiding in a priest-hole in Berkshire. Escorted to the Tower, he was tortured on the rack to try to secure a confession of treason.

Treason law veered in a sharply anti-Catholic direction due to an influx of Jesuit priests into the country

For those preparing Campion’s trial in Westminster Hall in 1581, it was vital to display him as a common traitor, not a religious martyr. They therefore based their charges on the 1351 Treason Act, claiming that his real goal was to destroy Elizabeth and stir up rebellion.

Campion, like Thomas More, put up a strong defence. His mission, he said, was purely pastoral and could not be interpreted as political or treasonous. Once on the scaffold he again adamantly denied that Catholicism equalled treason, but it was exactly that conclusion that Elizabeth’s regime was reaching. The public debate over whether Campion was a traitor or a martyr was long-lasting: in 1970 he was canonised by Pope Paul VI.

Guy Fawkes

The gunpowder plot was cast as the ultimate act of Catholic treachery

The gunpowder plot was the most notorious treason in British history. The public reputation of Guy Fawkes would endure for centuries but, unlike Campion, that reputation was wholly negative, perpetuated annually in popular culture on bonfire night.

The gunpowder plot conspirators shown in a contemporary engraving. Guy Fawkes is second from right.
The gunpowder plot conspirators shown in a contemporary engraving. Guy Fawkes is second from right. (Photo by Getty Images)

This demonisation was fully on display at Fawkes’s trial in January 1606. There was no doubt about his guilt: he had been arrested in the cellars underneath parliament, next to the barrels of gunpowder intended to blow up both king and parliament. Leading the prosecution case, Sir Edward Coke gave a speech full of hyperbole, exclaiming that “these are the greatest treasons that ever were plotted in England”. Coke portrayed treason like a tree: the “powder treason” had deep roots and had arisen “out of the dead ashes of former treasons” – in other words, out of Catholic treachery in the reign of Elizabeth.

While Fawkes’s guilt was clear, the authorities were less sure about his motivation. Historians agree that the plotters especially wanted revenge against an anti-Catholic regime. From 1603 they had expected toleration from the new Stuart king, James VI & I, and felt betrayed when this did not occur.

Fawkes, who had served as a Catholic mercenary abroad, felt that the violence of the regime should now be answered with violence. And he had an extra motive: his English patriotism and hatred of the “Scottish invasion”. The Scottish king James had united the crowns of Scotland and England and, as Fawkes told his Scottish interrogators, “his intent was to have blown them back into Scotland”. Fawkes’s fiery voice emerges from his interrogation. But it is Edward Coke’s version of events that has endured in English popular culture.

Charles I

To secure the conviction of Charles I, his accusers had to turn to the ancient traditions of Roman law

The mid-17th century was a violent age across Britain and Ireland, illustrated by the execution of King Charles I for treason. But how was this possible, when treason in law had always been a crime against the monarch?

The trial in January 1649 was the culmination of a decade of conflict between Charles and his parliament, with 200,000 people dying in England and Wales in the civil war. Parliament in the 1640s had also radically reinterpreted treason law, making it more of a crime against the state, in order to execute some of Charles’s key advisers. To prosecute the king himself, they accused him of “levying war” against his own people. The legal basis for this could not be the 1351 Treason Act. Instead, the court charged him under the ancient traditions of Roman law – which held that a ruler who was a “tyrant” could face justice.

Charles’s trial was a “show-trial”, for the victorious army leaders were determined to execute him for treason. They created a special High Court of Justice in Westminster Hall and carefully vetted the MPs who could attend. But they still wanted a show of legality for the public, so a formal procedure was followed and the king was instructed to plead. Yet Charles denied the army their propaganda coup by refusing to recognise the court. It meant that, although he was found guilty as a “public enemy to the Commonwealth of England”, he had rejected the way that treason was being interpreted.

More than a decade after his execution, following the restoration of the monarchy in 1660, the regicides themselves would be put on trial for treason. They were charged and executed under the 1351 Treason Act, as proof that the previous era had been one of gross illegality.

Alice Lisle

The fate of Alice Lisle in 1685 shone a harsh light on biased, bullying judges

In 1649, John Lisle had been one of the judges at Charles I’s trial. Thirty-six years later, the tables had turned and Lisle’s own wife, Alice, stood accused of the crime of treason. She would endure the same fate as the king.

Alice Lisle’s downfall was brought about by the disastrous Monmouth rebellion. The accession to the throne of the openly Catholic king James II had triggered an uprising led by James’s nephew the Duke of Monmouth. The duke invaded England at the head of an army but was soundly defeated in July 1685 at the battle of Sedgemoor in Somerset.

While Monmouth was executed as a “traitor” through an Act of Attainder, some 1,400 rebels were put on trial in the so-called “Bloody Assizes”. These were adjudicated by the sadistic lord chief justice, George Jeffreys, who already had earned himself a fearsome reputation for bullying witnesses to secure a guilty verdict.

The jury found Alice Lisle guilty, after the judge threatened to prosecute them for treason, too

Among his new victims was the 70-year- old Alice Lisle, unusual both by gender and age for being charged with treason. She was accused of harbouring two rebel traitors in her house in Hampshire – behaviour that Jeffreys claimed was just as bad a treason. At the trial, held in Winchester in August 1685, Jeffreys harangued the witnesses, threatening them with hell-fire. When Alice Lisle pleaded that she “abhorred the principles and practices of the late rebellion”, he repeatedly interrupted her with “evidence” of her guilt and hinted at the past anti-monarchical behaviour of her own husband.

Bloody denouement An illustration depicting the execution of the Duke of Monmouth. Some 1,400 men and women were put on trial in the “Bloody Assizes” that followed his failed rebellion.
An illustration depicting the execution of the Duke of Monmouth. Some 1,400 men and women were put on trial in the “Bloody Assizes” that followed his failed rebellion. (Photo by The Print Collector/Getty Images)

Despite this open bias, the jury found Lisle not-guilty three times: only on the fourth attempt did they convict, after a furious Jeffreys threatened to prosecute them for treason, too. Lisle was then beheaded in Winchester marketplace.

To the last, Lisle denied knowing that her visitors were rebels. Whether or not this was true, her conviction would be overturned by parliament after the fall of James II in 1688.

Her case also aided those pushing for the reform of procedure in treason trials. Through the Treason Trials Act of 1696, those on trial were finally allowed a defence lawyer, and the judge’s role was also curbed to stop the type of bullying witnessed under George Jeffreys.

Thomas Hardy

In 1794, the government – spooked by turmoil in France – embarked on an ill-fated attempt to prosecute a political radical

The 1700s saw relatively few treason trials in Britain. Yet all that changed in dramatic style at the end of the century – thanks to events on the other side of the English Channel. The outbreak of the French Revolution in 1789 made the British government increasingly anxious that revolutionary ideas would take hold. When, in 1793, French king Louis XVI was executed for treason and Britain found itself embroiled in war with France, those fears went into overdrive – as a shoemaker named Thomas Hardy would discover to his cost.

Hardy’s trial in 1794 served as a test case of Britain’s archaic 1351 Treason Act. Hardy was the founder of the London Corresponding Society, which campaigned for radical political reform. When he planned a public assembly to demand reform of the House of Commons, he was arrested as a revolutionary and charged with treason.

French terror In this satirical print by James Gillray, dating to 1795, sans-culottes attack the state coach carrying George III and driven by William Pitt. The French Revolution weighed heavily on many Britons’ minds. (Photo by Michael Nicholson/Corbis via Getty Images)
In this satirical print by James Gillray, dating to 1795, sans-culottes attack the state coach carrying George III and driven by William Pitt. The French Revolution weighed heavily on many Britons’ minds. (Photo by Michael Nicholson/Corbis via Getty Images)

At Hardy’s trial at the Old Bailey, the prosecution accused him of plotting to kill the king because he was challenging parliament: in other words, an attack on one was taken as an attack on the other. Hardy, however, was defended by Thomas Erskine, one of the most skilful defence lawyers of the era, and his tactics reveal well the impact of the 1696 trial reforms on court proceedings. Erskine ridiculed the idea that demanding political reform was equivalent to “imagining the death” of King George III.

The jury agreed, and Hardy was acquitted on 5 November (Guy Fawkes Day). His supporters triumphantly carried him around London and struck a medal in his honour.

After this failure to exploit the 1351 Act, William Pitt’s government in 1795 passed the Treasonable and Seditious Practices Act to modernise the definition of treason. It was now treason “to intimidate both Houses of Parliament” – plotting to overthrow the state, not just the king. The 1795 law was used repeatedly over the next few decades, notably in 1820 after the “Cato Street Conspiracy”: an ambitious plot by radicals to murder the entire British cabinet.

Roger Casement

The trial of Roger Casement, hanged in 1916 for seeking German aid, raised the issue of citizens with divided loyalties

Thomas Hardy may have defied the government in the law courts. But the Irish nationalist Roger Casement – who was charged with treason 120 years later at the height of the First World War – wasn't so lucky.

Casement’s trial again showed the difficulties of defining “treason” and of securing a fair trial. Before 1914, Casement had a huge moral reputation because he had exposed human rights abuses in the Congo and Peru. With the outbreak of war, however, he travelled to Germany to secure help for what he saw as the moral cause of Irish independence.

While admitting that he was a traitor to Britain, Casement wrote that “my country [Ireland, which was at that point ruled from London] can only gain from my treason”. He would, he believed, be betraying Ireland if he did not perform “a bold deed of open treason”. Yet German aid was lukewarm and in April 1916 Casement returned to Ireland, where he was captured and sent to the Tower of London to await trial.

Hostile environment Roger Casement leaves court during his trial in London, 1916.
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Casement’s crime seemed clear under the 1351 Act: he had given “aid and comfort” to the king’s enemies, behaviour that was even worse during a major war. Yet like so many “traitors”, he disputed the whole trial and took the moral high-ground. His allegiance, he said, was to Ireland: “If it be treason to fight [for Ireland], then I am proud to be a rebel, and shall cling to my ‘rebellion’ with the last drop of my blood.” He also objected to being tried in London, by a purely English jury, with a prosecution led by the attorney-general, FE Smith, who was notoriously hostile to Irish nationalism. The courtroom was stacked against him.Even worse, on discovering that Casement was homosexual, the authorities tried to discredit his moral stature. They leaked to the newspapers his “Black Diaries”, which graphically detailed his sex life.As with Edmund Campion, Casement’s trial revealed the split-allegiance at the root of so many treason cases. When he was hanged he, too, became a martyr – this time to the Irish nationalist cause.

Lord Haw-Haw

A passport proved crucial in sending Nazi propagandist William Joyce to the gallows

Everyone had heard of “Lord Haw-Haw” (William Joyce) during the Second World War. Joyce’s daily radio broadcasts from Nazi Germany had made him one of the most reviled men in Britain – a sentiment that was hardly improved by Hitler’s decision to decorate him for his work.

After his capture in 1945, the authorities were keen to set an example of Joyce, trying him, like Roger Casement, under the 1351 Treason Act for “aiding the enemy”. The jury found Joyce guilty in 20 minutes, and he was hanged in Wandsworth Prison in January 1946. He was the last person to be executed for treason in Britain.

Yet this easy conviction was problematic, even a miscarriage of justice. Although Joyce had committed the crime, it was discovered during his trial that he was not a British citizen and therefore not subject to British law. He had been born in New York and, though residing in Britain for 17 years, had never taken citizenship.

William Joyce, British Traitor who broadcast from Nazi Germany as 'Lord Haw Haw' during the First World War is pictured in captivity. He was hanged for treason.
William Joyce, the British traitor who broadcast from Nazi Germany as 'Lord Haw Haw' during the First World War is pictured in captivity. He was hanged for treason. (Photo by Getty Images)

The charge of treason therefore seemed weak, but the prosecutor, Hartley Shawcross, found another way to convict. When in England, Joyce had openly stressed his British allegiance, and had three times lied in order to secure a British passport. With this he had fled to Germany in August 1939 and retained it for a year before taking German citizenship. Because of this passport, Shawcross claimed that in 1939–40 Joyce had owed allegiance to the king in return for being under “British protection”. Instead, he had betrayed the crown.

Joyce claimed that he had tried to lead Britain towards friendship with Germany: “I know that I have been denounced as a traitor and I resent the accusation, as I conceive myself to have been guilty of no underhand or deceitful act against Britain.”

In fact, his conflicted loyalties entrapped him: in the end he was hanged for having a British passport.

Guy Burgess

The Cold War saw the emergence of a new security threat, headed by Britons working for the Soviet Union

The essence of treason has remained static through the centuries, as a crime that seriously endangers state security, often in collusion with a foreign enemy. However, the threats to British security have constantly shifted. Since the Second World War, treason has usually meant the betrayal of state secrets.

In 1955, foreign secretary Harold Macmillan spoke in the House of Commons about the case of the “Cambridge Spies”, Guy Burgess and Donald Maclean, who had just been exposed as traitors working for the Soviet Union. Macmillan explained that the landscape in Britain now resembled the era of Elizabeth I, with “traitor-spies” busy everywhere. Citizens were being attracted to communism, just as once they were drawn to Catholicism. But, he warned, the state now had to be careful to balance civil rights against the interests of state security.

English traitor and spy Guy Burgess, who fled to the Soviet Union in the early 1950s.
English traitor and spy Guy Burgess, who fled to the Soviet Union in the early 1950s. (Photo by Express/Express/Getty Images)

In our own age, the use of the archaic 1351 Treason Act has been abandoned although it remains on the statute book. Instead, as in the past, the British state has created a range of new laws for new dangers. When traitor-spies were prosecuted from the 1950s, they were usually charged under the Official Secrets Act, but more recently the government has employed terrorism laws against violent crimes once designated as “treason”. Yet with the evolution of security dangers, it’s been argued that new measures are required. In 2018, the think-tank Policy Exchange suggested that the 1351 Act should be reformed or replaced, in order to easily condemn as traitors those British citizens who fled abroad to help Islamic State (ISIS) in Syria and Iraq. So far, this idea of a new treason law has remained just that: an idea.

The history of treason in Britain has repeatedly revealed not only the difficulty of defining a crime that’s so inextricably linked with state power, but also the challenges of ensuring the accused are given a fair trial. With these two issues in mind, the jury is still out on whether we need a new law for British traitors in the 21st century.

Mark Cornwall is professor of modern European history at the University of Southampton. He is writing a history of treason in the late Habsburg empire, 1848–1918


This article was first published in the January 2022 issue of BBC History Magazine