Boe is working on the costume as part of a cross-border cultural exchange programme involving inmates from Mountjoy Prison and the infamous Maiano Prison in Spoleto, Italy.

In 1984, Boe was jailed for 16 years for the 1983 kidnapping of Sara Niccoli, 17. Shortly after, he and another inmate escaped from the high-security Asinara island prison and he became one of Italy's most wanted.

In 1992, he was captured in Corsica, extradited and sentenced to 20 years for the 1992 kidnapping of seven-year-old Farouk Kassam, during which the captors cut off part of the boy's earlobe. Boe's own daughter Luisa, 14, was shot dead in 2003; investigators suspected the killers mistook the girl for her mother.

David Collopy of Opera Ireland told the Sunday Tribune he visited Maiano Prison last week, where he opened three bottles of champagne with some prisoners and met Boe.

"At the moment, he's working on the costume for Parpignol, the toy seller who appears briefly in Act II, " Collopy said.

"As the opera will be set in the 1970s, it's going to be a gaudy outfit. The prisoners will work under a costumier. You should see the detail that's going into the toy seller's costume. It's hand-dyed and hand-stitched."

Collopy added: "These guys have run terror groups, they're not costumiers. I met one Mafioso who is now 84 and very feeble. In opera, people die on stage, but this guy put bullets in people's heads. They were given a copy of Vogue from the 1970s to show what people were wearing. Boe gave his opinion on the political situation in Paris at the time. This guy is scary, but also lovely. He was part of the Sardinian Separatists, not unlike the IRA. He was fighting for the liberation of his island."

John Costigan, artistic director of the Gaiety, said he is unaware of exactly who is working on props or costumes, or whose work will be used.

"When I first heard about the project, I said, 'Jesus, David, who will be on the sign-in sheets for the show?' In short, I don't know. I haven't had any discussions with David about it, but it's on the agenda."