FIVE STARS

THOMAS McCrudden leaves his cell, a feeling of dread crippling his innards. He sees a red mist. Not the stereotypical red mist “Tosh” McCrudden one of Scotland’s most notorious gangsters, may have seen before smashing, stabbing, slashing, bludgeoning, hacking and pulverising those among the vast numbers of victims that he directly harmed. No, it’s the red mist from the gouged wrists of a fellow inmate.

McCrudden stems the bleeding with his own hands, the same hands used to hold another youngster all night in an attempt to soothe his distress. “He wasn’t meant to be there,” says McCrudden, in front of us right now. “He was needing his mammy to cuddle him, not a monster like me.”

That’s visceral certainly, and it’s not for effect. Unfortunately, it’s reality – a reality you and I are largely protected from, and perhaps one we’d rather ignore. They deserve all they get, don’t they? People don’t change. And it’s all soft-soaping social workers, plasma telly and three square meals a day down the likes of “Hotel Barlinnie” these days, isn’t it?

But if you’re not changed or challenged in some way after this intense, extraordinary seventy minutes, I can only assume you’re a member of the exceptional, untrained cast here.

“Play” or “theatre piece” are unsatisfactory terms, as here is something beyond the commonly understood reach of those terms. It’s based on the writings of McCrudden, a man so feared that another young prisoner killed himself to escape his presence.

He dealt in violence so extreme we’d maybe call it “ultraviolence” were it not for that word’s association with flash, cinematic glamour. And when McCrudden first meets Mark Traynor (also played by himself), co-director of Grassmarket Projects with multiple Fringe First-winning scriptwriter Jeremy Waller, his response to Traynor’s delight at the brilliance of his prose makes it very, very clear the former attack dog has nothing but furious disdain for the idea of violence as entertainment.

The last time I can recall anything as powerful was Black Watch, the play which kickstarted the National Theatre of Scotland in 2006.

Doubting Thomas doesn’t need the high production values of that smash, nor is it likely to have the same mass appeal.

While Black Watch was nothing less than a serious piece of work, this is a more uncomfortable piece with no light to balance the shade, no redemptive flipside to the tragedies we’d rather not hear about.

Instead, it’s a searing indictment of low expectations, a criminal justice system that fails us all and the rotting abscess of sectarianism.

Neither is this about McCrudden attempting to salve his conscience. It’s almost as if, during that Bible black night of the soul where his victims’ suffering rebounded on him like some sort of cosmic re-ordering, McCrudden’s ego was obliterated.

He’s not seeking forgiveness for the terrible things he did, he’s seeking accountability from his fellow criminals and radical change on behalf of wider society and the generations of “lost boys” who have taken his place.

“If we don’t embrace them, others will,” he warns with an impassive chill. “And then they will hurt every single one of us.”

Until Aug 28, Summerhall (V26), 7.20pm (70mins), £10, £8 concs. Tel: 0131 560 1581.