In direct violation of the Treaty of Union, English treason law was now used in Scotland, and an English barrister, John Hullock, was sent to conduct the prosecution, despite his having no legal qualification in Scotland. A special commission headed by Lord President Hope and others, and a grand-jury of propertied anti-Radicals, some of whom served in the yeomanry,  proceeded to find bills against Radical prisoners held at Stirling and Glasgow. On 28 June, after the military held a parade in Glasgow, trouble broke out between the English soldiers of the 13th Regiment of Foot, and the inhabitants. The English soldiers, having imbibed at a tavern, roamed the streets insulting the Scots and Scotland and charged up to Glasgow Cross with bayonets stabbing at Scots as they went. When the city police were called in, the English soldiers attacked them too and later rioted at the police station. The authorities tried to cover up the incident and later claimed the soldiers had been provoked.

The commission headed to Paisley on 1 July. As the band of the 13th Regiment of Foot struck up God Save the King the Radical prisoners sung Scots, Wha Hae as loudly as they could from their cells for which they were put in chains. The crowd in Paisley showed itself hostile to the authorities and soldiers throughout. The indictments concluded in Ayr on 4 July and the state treason trials began in Stirling on 13 July 1820. Altogether 88 people were indicted for high treason of whom some had escaped. Asked to defend the Radicals, leading Scottish advocates at first refused to take part in a trial held under English law, but later agreed only if assisted by agents sent from England who had knowledge of English law. Leading advocate Francis Jeffrey began by making legal arguments against English law in a court in Scotland. As a result the petulant English prosecutor Hullock made derogatory remarks about Scotland and her people throughout the trial. The trials concluded in Ayr on 9 August. Of those tried 19 were sentenced to transportation to Australia, seven for life, and twelve for fourteen years. In addition, John Baird, Andrew Hardie and James Wilson were to be made particular examples by being drawn, hung, beheaded and quartered, though the sentence was changed to hanging and then beheading after death.  

James Wilson, the 63 year old from Strathaven (pictured), was the first to be executed. On 30 August 1820 he was taken to the Justiciary Hall in Glasgow where a crowd of 20,000 watched him being put to death. There was a huge military presence consisting of a rifle brigade, the 33rd Regiment of Foot and 3rd Dragoon Guards. A Glasgow medical student named Thomas Moore was the executioner. He wore a black mask and carried an axe and knife. James Wilson was drawn to the scaffold, hung by the neck, and once he was dead, he was beheaded and the head held up to the crowd. There were shouts of ‘murder’ and ‘martyr’ and the dragoons at one point charged the crowd. John Baird and Andrew Hardie were executed in front of Stirling jail on 8 September 1820. Once again the executioner was medical student Thomas Moore and the crowd was about 2,000 strong. Baird and Hardie were drawn to the scaffold on a hurdle, made speeches, and then were hung by their necks. They were then beheaded like Wilson and the crowd shouted that it was murder, but under the watchful gaze of the soldiers, they dispersed home.

Wilson, Baird and Hardie, who gave their lives for political reform, have ever since been known as the 1820 Martyrs. Along with them we remember those who were transported to Australia: John Anderson (Camelon), John Barr (Condorrat), William Clarkson (Glasgow), James Clelland (Glasgow), Andrew Dawson (Camelon) , Robert Gray (Glasgow), Alexander Hart (Old Kilpatrick), Alexander Johnston (Lanarkshire, aged 15), Alexander Latimer (Glasgow), Thomas McCulloch (from Co Down, living Glasgow), Thomas McFarlane (Condorrat), John McMillan (Camelon), Benjamin Moir (Glasgow), Allan Barbour Murchie (Dunfermline), Thomas Pike alias Pink (Glasgow), William Smith (from Ireland, living Condorrat), David Thompson (Glasgow), Andrew White (Glasgow, aged 16) and James Wright (Glasgow).