In April 1938 the IRA Army Council elected Sean Russell as Chief of Staff. He asked a senior volunteer named Seamus O'Donovan to draw up a plan to extend the campaign against British rule in Northern Ireland onto the British mainland itself. O'Donovan's strategy, called the Sabotage Campaign and known within the organisation as the S-Plan, was approved that August. The first attacks fell in January 1939, on cinemas, post offices, power stations, gas mains, and luggage racks in London. By August 1939 Coventry had been targeted six times. None of the previous bombings had killed anyone. The Coventry IRA cell, led by James McCormick (operating under the alias James Richards), prepared one more attack. Peter Barnes, a courier who had brought the explosives from London, delivered them to McCormick. McCormick built the device. Somebody pushed the bicycle along Broadgate at lunchtime and walked away.

Broadgate in 1939 was the commercial centre of Coventry, a busy shopping street lined with jewellers, booksellers, cafes, and the spire of Holy Trinity rising behind the rooftops. The H. Samuel shop window was a magnet, the kind of display where young women browsed in the lunch hour. Elsie Ansell was the closest person to the bicycle when it exploded. Her injuries were so extensive that her body could only be identified by her engagement ring. John Corbett Arnott and Rex Gentle worked at the WH Smiths a few doors down and were walking back to work together. James Clay had just shaken hands with a business acquaintance outside a cafe. Gwilym Rowlands was on his knees at the kerb when the blast hit. The seventy injured were rushed across town to Coventry and Warwickshire Hospital. The most seriously hurt, a 43-year-old named Harold Murdock, died eight months later of injuries the coroner ruled had accelerated his death. The last survivor to leave hospital was a fourteen-year-old girl named Muriel Timms, who had sustained severe leg injuries and remained an inpatient until February 1940.

Suspicion fell on the IRA within hours. Peter Barnes, when asked by detectives whether he had been to Coventry that day, replied that yes, he had, but Coincidences can happen, can't they? He was arrested on the spot at Canon Row police station in London. On 28 August Coventry City Police, working with Special Branch, searched a terraced house at 25 Clara Street that had been used as the cell's safe house. They found a suitcase still bearing traces of potassium chlorate, pliers, solder, insulating tape, fragments of a dry-cell battery, and a brass setting device for an alarm clock that did not match any clock in the house. All the occupants of the property were arrested under the Explosive Substances Act 1883, including James McCormick. Five people were eventually charged with the murders. Barnes and McCormick were both convicted and hanged at Winson Green Prison in Birmingham on 7 February 1940. They were the last members of the IRA to be executed in England.

Coventry was bombed again, much more severely, a year later. On the night of 14 November 1940 the Luftwaffe raid that gave the German military the verb coventriern, to coventrate, destroyed the medieval cathedral and over four thousand homes. The five who died in Broadgate in August 1939 were buried beneath that subsequent enormous grief. The bicycle bomb became a footnote, a forgotten attack on a British city, in the words of a 2014 BBC headline. In October 2015 the city finally dedicated a permanent memorial to the five victims in Broadgate, on what is now a pedestrianised shopping precinct. The names are listed. There is a small plaque. The Irish Post covered the unveiling. The Irish Times sent a reporter. Most people who walk past it do not know what it commemorates. The families of Elsie Ansell, John Corbett Arnott, Rex Gentle, James Clay, and Gwilym Rowlands have always known.