He was considered among the leading young activists in the organisation in the early 1950s along with Charlie Murphy, Robert Russell, Tom Mitchell, Ruairí Ó Brádaigh and Joe Christle.
[2] Boyce was later captured leading an IRA arms raid on the military barracks in Omagh, County Tyrone, on 17 October 1954, for which he was sentenced to twelve years' penal servitude in Belfast Gaol.
He had previously been unaware of the organisation's existence, believing it long since disbanded since the end of the Irish Civil War, when he passed by a large billboard advertising an upcoming Sunday exposé on the IRA in an English newspaper.
[6] Boyce's attention was attracted to "a trench-coated figure carrying two guns", in particular, and initially thought the portrayal was related to the Irish War of Independence.
When he mentioned this to his companion, Matty O'Neill, a former Curragh internee, remarking on the garishness of the advertisement, Boyce was surprised when the older man replied "Sure, them that's running it now don't mind."
[6] A year later, Boyce, now Intelligence Officer, and Charlie Murphy began developing a plan to raid a British military barracks in Northern Ireland for weapons and other supplies.
The party split up at a dump in County Meath, upon meeting with IRA Chief of Staff Tony Magan, with some making their way back to Dublin by bus.
They eventually attracted the attention of a Garda police car on the outskirts of Dublin, having heard news of the Armagh raid, and attempted to block the road.
[6] They were questioned by police but were released partly due to lack of evidence, nothing save two revolvers were found in the truck, and the Irish government's embarrassment over the incident.
[6] On the night of 16 October 1954, Boyce led 35 men in a second weapons raid in Omagh, County Tyrone, the supply depot for the Royal Inniskilling Fusiliers.
Boyce got as far as the Clogher Valley area, and while taking off his boilersuit in a ditch,[6] he was captured by a Protestant farmer and his five sons, all of whom were heavily armed.
He reportedly experienced some degree of police brutality following his capture, being "cuffed about" and forced to dress and undress in his wet clothes six times, before being transported back to Omagh to stand trial.
At his trial, which he and his men refused to recognise, Boyce told the court "This war was not waged against any Irishman, but against a foreign Queen who has no right to have her forces on our soil.
[9] He was in poor health at the time, having trouble with his nerves, preventing him from "any of the normal things prison keeps a man from doing" such as crossing a street unaided, walking into a shop or applying to a labour exchange.
He learned that his mother had also suffered during his incarceration, not only because of the emotional stress, but through the loss of Boyce's income and reportedly unknowingly aiding his accomplices; for months, several hundredweights of gelignite had been hidden under her bed.
He was eventually able to get his job back as a bus conductor and later married Dympna McConnell, a grand-niece of Michael Mallin, Chief of Staff of the Irish Citizen Army, executed on 8 May 1916 for his part in the Easter Rising.