Peter Barnes was born on 6 May 1907 in Banagher, King's County (now Offaly), Ireland. As a young man, he was deeply influenced by Irish republican ideology and joined Fianna Éireann, a youth movement tied to Irish nationalism. His commitment to the republican cause led him to become a full member of the Irish Republican Army (IRA) in 1924, at just 17 years old.

During the interwar years, Ireland was still navigating the tensions left by the War of Independence and Civil War. Many young men like Barnes grew up amid political unrest, which shaped their beliefs and, in many cases, their willingness to engage in armed struggle. Barnes believed in Irish unification and saw the British presence in Northern Ireland and the Republic’s lack of full independence as a betrayal of Irish sovereignty.

By the late 1930s, Barnes had become involved in the IRA’s S-Plan (Sabotage Campaign), a strategy designed to carry out bombing attacks in England to disrupt and destabilize British control. It was during this campaign that Barnes would be arrested and later executed.

He was engaged at the time of his arrest, and his fiancée’s address was searched by authorities who found materials linked to bomb construction. Throughout the investigation and trial, Barnes remained defiant, insisting on his innocence in the specific act of placing the bomb, though he admitted to having built it

On 25 August 1939, a bomb exploded in Coventry, England, killing five civilians and wounding many others. The bombing was part of the IRA’s S-Plan, a coordinated sabotage campaign designed to pressure the British government through attacks on infrastructure and public targets. The intended target was reportedly a power station, but the bomb detonated prematurely or was mishandled, leading to civilian casualties.

Peter Barnes and fellow IRA volunteer James McCormick (alias James Richards) were arrested that same day in London. In Barnes’ room, investigators found the address of his fiancée, and at her home, they uncovered receipts for materials commonly used in bomb-making.

During interrogation, both Barnes and McCormick admitted to constructing the bomb, but denied planting it, claiming they believed it would be used against infrastructure, not people. Another IRA member, Joseph “Joby” O’Sullivan, later claimed responsibility for planting the bomb and insisted that Barnes and McCormick were not involved in that part of the operation.

Nevertheless, both men were charged with murder under the British legal doctrine of common purpose, which holds all participants in a criminal enterprise equally liable if the action results in death. The jury deliberated for just 31 minutes before returning a guilty verdict on 15 December 1939.

On 7 February 1940, Peter Barnes and James McCormick were hanged simultaneously at Winson Green Prison in Birmingham.