IT took Elizabeth McWilliams 63 years to tell the world what happened to her as a child in the care of the Quarriers Homes, a charity built on the Christian principles of love and fellow feeling.

So painful are her memories that she has to read from a prepared statement describing the beatings, sexual assault, neglect and psychological torture she suffered at the hands of care-home staff in the 1930s, 1940s and 1950s.

Her testimony is now a major part of an extensive investigation by Strathclyde Police into systematic abuse at the home. Her claims even go as far as describing an apparent attempted murder to which she was the eyewitness.

In September last year, Samuel McBrearty, aged 70, was jailed for 12 years for raping and assaulting three children at the Quarriers Homes 30 years ago. He had been one of the most respected social workers in Aberdeen before his arrest.

Now one of Scotland's largest and most respected child-care charities, Quarriers is facing a series of allegations of abuse by former child residents, including McWilliams. The charity, which still runs residential units for children with special needs, is facing compensation settlements of hundreds of thousands of pounds.

Abandoned as a baby of six months, McWilliams and her twin brother Jack were sent to the Quarriers Village in Bridge of Weir - a self-contained community of 46 shared cottages for deprived children and orphans - in 1937. Sixteen years later, she emerged into the world illiterate and physically and psychologically scarred for life.

Her tormentor-in-chief, she claims, was one Frances Bowman, the house mother of Cottage 11 where McWilliams was housed throughout her stay. With grim irony, Bowman compelled the girls to call her "Mama" even though she was violently assaulting them.

"I had no identity as a child except as a victim," she says, continually breaking into sobs.

The best treatment a child could expect was to be woken before dawn and forced to undertake gruelling chores. "I had no compassion or love shown to me. It was a house of horrors. I was a slave in a labour camp. I was tortured physically and mentally, sexually abused, and whipped with a belt that was never out of Mama's hand.

"I screamed at her, 'Mama, stop!' and she'd say to me, 'Go on, scream, no-one is listening, you're a guttersnipe'. I was beaten black and blue. When she'd finished beating me, she'd push me up to my neck into a bath of freezing cold water, thinking it would make the bruises go away. I'd have to stay in the icy bath for half an hour at a time.

"The food was ghastly. If you got something horrible like lumpy porridge and couldn't eat it, you'd be given it for lunch and then again for dinner. This would go on for days until it was eaten.

"I was totally at her mercy. We were treated like animals. She'd take me out to a pigswill bin and lift the lid and stick my face into it. The smell was revolting. I'd vomit. Then she'd make me fill a pot with it and put it on the stove and cook it. We'd sit at the table, all of us together, and say grace before having to eat it.

"We'd thank God for what we were about to receive, and it was pigswill. Then we'd have to say grace again at the end, telling the Lord that we were thankful for what we had received. All this was done in the name of Christianity.

"I've been left with the most terrible scars in my heart - they will remain with me forever. Terrible things happened in Cottage 11. I remember a friend of mine, Molly Dobbie, who was about 10. Mama took her by the hair and threw her down the stairs.

"Molly's head hit the tiles at the bottom with a most awful bang and Molly just lay there motionless. Above her on the wall was a picture of Jesus with the words 'Christ is the head of this house'.

"Mama came down after her and grabbed her by the hair and told her to get on with cleaning the stairs, but she wasn't conscious. She was never the same girl again. It was an attempted murder. Molly died of epilepsy years later. It was horror.

"Then there was my friend Georgina Rosie. She was the same age as Molly. Georgina wet the bed all the time. In the morning Mama would rub her nose in her wet sheets. Georgina had to wash her sheets and nightgown every night. If it was raining and they weren't dry she went to bed without them.

"She was also deprived of fluids to stop her wetting the bed. To get a drink of water, she'd flush the toilet and then cup the water in her hands to her mouth. She ended up in a lunatic asylum."

Visitors used to come to the home from religious organisations and the children were ordered into their Sunday best. I As soon as the visitors left, applauding the good work of Quarriers, the abuse would begin again.

McWilliams says her twin brother Archie ended up an alcoholic and almost destitute after the abuse he suffered. "He told me he drank to blank out what they did to him," said McWilliams. "We were beaten over nothing. We didn't know what we had done wrong. We just thought being beaten was a way of life."

The worst abuse came at the hands of a man McWilliams only remembers as Mr McCracken, a house father at Cottage 22 and a joiner by trade. One afternoon when she came in from school, he was in her dormitory fixing a window.

"He said to me, 'Come here girl.' I said, 'Yes, sir' and walked over to him. Then he said to me 'Get your knickers down, girl'. McWilliams suffered a serious sexual assault. "When it was over he told me to get dressed and get back to work because he was finished with me."

This was the only time that McWilliams was sexually assaulted at Quarriers. "I couldn't tell Mama as she wouldn't have believed me. I don't know if this happened to the other girls."

Frances Bowman was house mother for 30 years. She is now dead, says McWilliams, who wants any surviving Quarriers staff who were in charge of running the home prosecuted for their alleged crimes.

When she finally left Quarriers, aged almost 17, she eventually secured a job as a nursing auxiliary with the Royal Infirmary in Glasgow. That's where she met her husband, Jack. "When he asked me out I was terrified. I remembered the abuse that happened to me and thought I could never go out with a man. But he persisted and said he liked me.

"We had the most lovely first date. He took me for a meal and I'd never been in a restaurant before. He walked me back home and at the gate he told me he loved me. Thai was the first time anyone had ever said that to me. I burst into tears and he couldn't understand why."

They married the next year, and they had three sons and a daughter. When her daughter, Jacqueline, was born, McWilliams made her husband swear that her child would never have the same life she did. Today Jacqueline is a graduate and a first lieutenant in the Royal Navy.

McWilliams has made four suicide attempts. It was after one of these that she finally told her husband about her time in Quarriers. "When I came out of the hospital, he begged me to tell him what was wrong. I told him I was terrified of losing him and he said, 'You'll never lose me.' I told him and he just hugged me and said, 'No, no, no' over and over again."

Her husband died last year. "His final words to me were 'I love you'," she says. "For 16 years of my young life, I was robbed of the most precious thing that God gave a child and that's the priceless gift of all: love." In March, the police called at her door on a tip-off from another Quarriers resident that McWilliams had suffered abuse as well.

It was then that she told the whole story to both officers and her children. Strathclyde Police confirmed McWilliams had been interviewed "as part of a wider investigation into allegations of abuse at Quarriers Homes'".

Phil Robinson, Quarriers chief executive, said of McWilliams's allegations: "We know police are investigating further allegations of abuse. Our position is that obviously we are appalled that such things could have happened and we are co-operating fully.

"It is right that these people are prosecuted and punished. The main thing that emerges is that during that period there were no efficient vetting procedures in place.

"I have the greatest sympathy for anyone who suffered this kind of abuse and my heart goes out to them if they have to relive their ordeal in a trial. The vetting procedures today are unrecognisable from those of the past."