A dozen people were killed and many more severely injured when a bomb left in a wheelbarrow outside a prison wall in Clerkenwell, London, in December 1867 exploded. The terrorists responsible believed it would bring down the wall and allow Irish Republican prisoners to escape.

The man alleged to have laid the charge in the wheelbarrow was Michael Barrett, 27, an Irish Republican born in County Fermanagh. Months earlier he had been arrested in Glasgow, then freed, for discharging a firearm. But at the Old Bailey in April 1868 he called witnesses who testified that he was in Scotland on the day of the Clerkenwell explosion.

The prosecution’s case against him rested on evidence of a Dubliner, Patrick Mullany, who had given false testimony before and whose reward was a free passage to Australia. He told the court that Barrett had informed him that he triggered the explosion with an accomplice named Murphy. Despite lack of corroboration, the jury found Barrett guilty of murder. He was hanged on Tuesday, May 26th, 1868, outside Newgate Prison before a “vast concourse of a crowd.” The hanging made history, being Britain’s last public execution.

The Clerkenwell bombing was the most serious terrorist action by Irish Republicans in Britain in the 19th century. It arose from the arrest in November 1867 of Richard O’Sullivan-Burke, a senior Republican arms agent. He was incarcerated in Clerkenwell Prison and the explosion was intended to blow a hole in the wall and rescue him. It was seriously misjudged; it demolished not only a large section of the wall, but also a row of tenement houses opposite.

Queen Victoria was outraged that only one man went to the gallows. She urged that in future, instead of being brought to trial, Irish Republican suspects should be lynched on the spot.

However, a socialist Sunday newspaper summed up much of the popular feeling: “Millions will continue to doubt that a guilty man has been hanged, and the future historian of the Fenian panic may declare that Michael Barrett was sacrificed to the exigencies of the police, and the vindication of the good Tory principle, that there is nothing like blood.”