Clive had been committed due to the terrible, demonic hallucinations he experienced after the death of his mother Picture posed

The Occupational Therapy Unit at St Vitus's, an adult psychiatric hospital, was a long room with a dirty, vinyl floor and high windows, the lower panes of which were obscured by opaque plastic sheets.

I was there to see a 13-year-old boy named Clive Plummer. (All names have been changed). He had been committed due to the terrible, demonic hallucinations he experienced after the death of his mother.

I had been asked to meet him by his sister, Roberta, whom I had been to college with. She was convinced there was more to his apparent breakdown than met the eye — I wasn't so sure, but wanted to help her.

Clive was in terrible physical shape — thin, hollow-eyed and scarred from self-harming. He wore an expression devoid of feeling, and sat perfectly still, gazing unblinking into space.

I extended my hand.

"Clive, my name's Shane. I'm a friend of Roberta's, and she's asked me to come out and have a chat. I'm very pleased to meet you."

"I don't know you," he said tonelessly.

"I'm a friend of Roberta's."

"They sent you, didn't they?" he hissed at me, fighting to get the words out.

"Hey, relax, Clive. I promise you, I'm here because Roberta asked me to come."

"You can't fool me," the boy hissed. "I've been waiting for you. You're from them... I can tell."

"Who are they, Clive?" I asked, trying to calm him. "Who do you think is trying to hurt you?"

And then he was on top of me, knocking me backwards off the chair onto the linoleum, screaming, spitting and snapping at me with shattered teeth.

For a boy of his size, Clive was powerfully strong, and it took every ounce of my weight and the momentum of our fall for me to roll over, so that I was on top of him. Medical staff rushed over, a shot was administered, and poor Clive was taken away.

It took me several weeks to build up a relationship with Clive Plummer. Despite three visits accompanied by Roberta, the boy continued to be cautious. Gradually, through perseverance, trust grew and he felt able to tell me about the visions that haunted him.

"I'm here, in the hospital, and it's night time," he began, haltingly.

"I'm the only one on the ward, and when I go to the door, it's open. I walk out into the corridor. I know I shouldn't, but I keep going. I can see a light away in the distance, and I can hear something, like voices praying or chanting.

"The sound sort of pulls me forward. As I get closer, I can see that there's someone — something — standing at the end of the passage."

His voice was cracking, as if his very being did not wish for him to continue this narrative.

"You don't have to tell me this if you don't want to, Clive," I said quietly.

"I need to. I have to tell someone." He looked at me, and the terror was etched into every line in his face — I thought, as I watched him, that 13-year-old boys shouldn't have lines on their faces, but Clive did.

"You believe me, don't you, Shane?"

"I know something awful happened to you, Clive."

I paused, squeezing his shoulder in an attempt to anchor him here with me, with the smell of grass and trees and frozen earth. "What's at the end of the corridor, Clive?"

"One of them."

"Who? Who are they?"

"Not who. What."

"I don't understand."

"See, Shane, they're not men. Standing at the end of the hallway is their leader.

"He's tall, much taller than you. His body is like a man, but the head is like a goat or a bull.

"It has horns and eyes like a cat, and smoke and fire come from the nose when he breathes. The monster wants me back. In my dreams, he tells me he's coming."

I was in the office several days later when the call came from Roberta Plummer.

"Clive's had an episode."

I paused in pushing a piece of paper into a plastic folder, the phone cradled between my chin and shoulder.

"What kind of episode?"

A pause, then: "He attacked a nurse and almost killed her. He ... he tried to rip her throat out. Scratched her with his nails. Broke her arm. They said he almost tore her cheek off with his teeth."

I went in to the hospital to see him immediately, and found him strapped to his bed in great distress.

"You led them to me," Clive said, glowering at me from the bed. "You tricked me into being your friend, and then you brought them here."

I learned that Clive's violence had occurred after a visit from a priest. This visitor turned out to be a close family friend of the Plummers', Fr Eddie, but when I spoke to him, he exuded sympathy and compassion for Clive. He told me he was certain the nightmares and hallucinations were linked to Clive's fascination with the occult, yet a second visit to Clive's home revealed not a single Tarot card or book on witchcraft — it didn't add up. I was no closer to learning why my client had regressed so badly.

I found out a week later.

On a visit to the hospital late one evening, I got talking to a cleaner, who told me her name was Mildred. She was a handsome woman in her late sixties, and we struck up a conversation over a hurried cigarette.

During the course of our chat she mentioned that she knew Fr Eddie.

I raised an eyebrow. "How do you know him?"

She lowered her eyes, scuffing the ground with her toe like a child might. "Do you know what a Magdalen is?" she asked.

"You mean the women who were in the Magdalen laundries?" I asked.

"Yes. I am — I mean I was — a Magdalen."

Magdelan laundries — veritable prisons for so-called fallen women — were operated by different orders of the Roman Catholic Church, most famously the Sisters of Mercy and the Good Shepherd Sisters.

"Fr Edward used to visit us in the Laundry," Mildred said. "Some of the priests who came to see us were decent, but some were devils. He was one of the worst."

Fr Eddie had a history. He had been investigated for alleged abuses in several parishes, and was said to have an obsession with the more mystical and arcane side of the Catholic Church. As a priest told me: "Clive Plummer may not be interested in the occult, but Fr Eddie most certainly is."

It was too much of a coincidence. I decided to speak to the boy's father. When I met him, he broke down.

"When my wife became ill, Fr Eddie asked her to attend some prayer evenings at the presbytery," he said.

"I didn't realise until she'd been to a couple that they were actually more a kind of pagan gathering. I think it was after the third or fourth one she asked me if she could take him.

"She told me that Fr Eddie had told her that, because Clive was her son, he'd amplify her natural energies, accelerate her healing. Clive said he'd be glad to go — he was completely devoted to his mother — and I thought no more about it.

"The boy was a bit reserved after some of the meetings, but he's a teenager, I passed it off as adolescence. My wife admitted to me that there was a sexual element to some of the ceremonies they performed, and that perhaps this was stirring up some hormonal issues for Clive. I told her I didn't want him witnessing anything inappropriate, but she laughed and told me it was more imagery and suggestion than anything else. So I said no more about it. I never thought for a moment she'd allow anything harmful to happen to our son."

"But she did, didn't she?" I said.

"I didn't find out what they'd done to him until it was too late," Plummer said. "My wife was in hospital, by then, and knew she was going to die. She wanted me to get Clive help.

"She realised what she had done was wrong, but she was desperate for a cure. I can't be angry with her. Wouldn't it have been better for him to have a mother? She thought that was what she was doing, you see. She was trying to live."

"Mr Plummer," I said, unable to hide the disgust in my voice, "in her effort to live, your wife almost killed her son. Your son."

Fr Eddie flatly denied the allegations of abuse, almost challenging me to bring any charges against him.

"They've tried to put me away before, Mr Dunphy," he crowed. "It didn't work then, and I don't think it'll work now. But feel free to try."

I told him to be quite certain that I would make every effort to do just that.

'She thought it would make her get better, didn't she?" Clive said. "That by doing those things, the cancer would go away." It had not been easy to tell him, nor for him to understand what had happened.

"I don't remember any of it," Clive said. The sedatives they were pumping him full of had been reduced, but he was still a bit groggy. "All I can see when I try to is the monsters. It's dark and they're all around me, hurting me. Mum isn't there."

"I think your mind created those nightmares, as strange as it might seem, to protect you," Roberta said. "What happened was really, really awful. I suppose being attacked by demons seemed better than ... than what really did occur."

"I wish she was here," Clive said.

"I know," Roberta said, putting her arm around her brother. "She owes you answers, and an apology. She owes us both that."

"No," Clive said. "I wish she was here so I could tell her I understand. That I forgive her."

Clive Plummer was taken off all medication shortly after his father finally faced the truth, and was allowed to go home shortly after that.

Roberta took a career break, to help her brother cope with the reality he had been forced to accept, and she and Clive are, to the best of my knowledge, still in therapy. Clive's father died a year later.

The Roman Catholic Church has left a legacy that will continue to reverberate through Irish society for many decades to come. It is a shameful thing that they continue to duck and dive, and to harbour individuals they know are a danger to children. The man I based Fr Eddie on was, eventually, prosecuted, on a lesser charge. He served 10 months, and is at large again, now.

Children and teenagers continue to be put in adult psychiatric facilities. The need for child and adolescent beds has been highlighted countless times, to no effect.

'Hush, Little Baby' is published by Gill & McMillan, ˆ11.99

- All names have been changed