Convicted killer Michael Stone stormed the Irish Parliament with enough homemade bombs to kill dozens in a rain of fire and nails.

But it was all in the name of art, he says.

The lifelong terrorist, now awaiting judgment in Ireland for his November 2006 raid on the Stormont Parliamentary Building in Belfast, is trying a novel defense against the attempted murder charges he's facing: His bombs were part of an innocent performance art installation and nothing more.

The 53-year-old Stone was caught red-handed with a hoard of 18 deadly weapons he says were props in his one-man show. The nail bombs were meant to symbolize "nailing the truth," he told a court in testimony in September — but that's a line prosecutors aren't buying.

According to the testimony of explosives expert Gerard Murray, this so-called "performance art" could have caused what he called "horrific" burns and death.

It wouldn't have been the first murder for Stone, once called the "Stone Cold Killer" for his gun-and-grenades attack on an IRA funeral in 1988 that left three mourners dead. Stone, who joined a paramilitary group at the age of 16, spent 12 years in prison for a total of six murders — but was released in 2006 under the terms of a peace accord between Britain and Ireland.

• Click here to see more photos of the 'Cold Stone Killer'

Stone has admitted to receiving extensive training in building improvised bombs and firearms during his years of internment at Long Kesh prison outside Belfast — training that could have made his bombs something deadly.

If the explosives had detonated, experts say the pipe bombs he constructed would have shattered into thousands of sharp pieces moving at extreme velocity. Typically, a person would suffer multiple puncture wounds causing massive bleeding, which makes triage and care very difficult.

For this reason, nail and pipe bombs are particularly attractive to terrorists because they are especially deadly to civilians in an enclosed area like a bus, plane or small room, where the effect is magnified by both the shock wave and the shrapnel bouncing back and forth.

And even the bomb's shockwave alone can be lethal — killing you by literally squashing your insides.

Stone claimed he constructed the bombs out of plastic rather than metal as evidence of his innocence. However, experts say although plastic is less likely to produce sharp fragments that would penetrate body and would have a smaller kill radius, it would be a more intelligent choice for a terrorist trying to evade detection by metal detectors.

Security experts are chilled by the prospects of Stone's acquittal on his artful dodge.

"It is important not to let a precedent be set that would prevent terrorists from facing due prosecution," said Kate Clouston, head of the Transatlantic Security Program at the Royal United Services Institute for Defense and Security Studies. "That would be less than ideal."

Yet Stone's counsel found an art critic willing to testify that the bombs really might constitute a form of art.

Peter Bond, a senior art lecturer at St. Martin’s College in London, testified that as long as Stone was not intending to set off his explosives, they could fall "under the ambit" of performance art.

Disturbingly, this is not the first time a would-be terrorist has used an artist's defense in Europe. Samina Malik, the self-styled "Lyrical Terrorist" who was the only woman ever convicted of terror-related crimes in Britain, told a court in 2007 that her plans for martyrdom were nothing more than poems written to entice men to marry her.

The 23-year-old, who worked at Heathrow Airport, hid her thoughts in poems with names like "How to Behead" and possessed a library of extremist training manuals — but got off with nothing more than a slap on the wrist.

Click here to read more about Samina Malik.

If the court is swayed by this preposterous defense, it could set a precedent unleashing the floodgates for any terrorist to get off scot-free by claiming his botched terrorist attempt was merely bad performance art.

Allison Barrie consults at the highest levels of defense, has travelled to more than 70 countries, is a lawyer with four postgraduate degrees and now the author of the new book "Future Weapons: Access Granted"  covering invisible tanks through to thought-controlled fighter jets. You can click here for more information on FOX Firepower columnist and host Allison Barrie and you can follow her on Twitter @allison_barrie.