ONE of the alleged victims of abuse by a nun at a children's home run by the Catholic Church yesterday told a court that another nun had sex with a workman as one of the youngsters kept watch.

Mrs Helen Cusiter, 43, made the allegation during cross-examination at the Aberdeen Sheriff Court trial of 58-year-old Marie Docherty - Sister Alphonso - who denies 23 charges of abusing young girls aged from two to 17, by cruelly and unnaturally treating them at Nazareth House homes in Aberdeen and Midlothian between 1965 and 1980. The charges include forcing girls to kiss dead nuns, making one girl spend the night in a chapel with the body of a nun, punching, slapping, kicking, and hitting girls, and placing them in a state of fear and alarm.

Mrs Cusiter told Mr Paul Cullen, QC for Sister Alphonso: ''Sister Gertrude was having an affair with one of the workmen.''

She said Sisters Gertrude and Alphonso disliked each other and it was because of that Sister Alphonso had reported the other's affair to the mother superior.

''They portrayed Nazareth House as fluffy and full of love but in those days it was far from it. There was a lot going on,'' she said.

''And this was well known?'' asked Mr Cullen, ''Yes,'' she replied.

''It was the talk of the steamy?'' he asked. ''There was great excitement,'' she replied. ''She put one of the children on look out for her while she was fornicating.''

Earlier Mrs Cusiter, the first witness in the trial, told of assaults on her by Sister Alphonso including one in which she was pushed off a swing, hitting her head on a wall, smashing four front teeth.

She also alleged that when she started to menstruate Sister Alphonso had called her a ''dirty bitch'' and told her she would be dead my midnight as ''God's punishment''.

She claimed that on her 13th birthday she stole a box of Smarties from a shop because she was not getting a sweet, and when she was caught by Sister Alphonso ''she absolutely beat the life out of me near enough - that was one of the real severe ones''.

Mrs Cusiter said she was punched, kicked and thrown around a room and it only stopped when Sister Alphonso thought she was unconscious.

She said she managed to block out the memories of her time at Nazareth House to the extent she enrolled her own son in its nursery school in the early 1980s. A chance meeting with Sister Alphonso in 1992 brought back memories which had plagued her for the last eight years, leading to the severe psychiatric problems for which she is now on constant medication.

Mrs Cusiter recalled she would visit Nazareth House occasionally to meet Sister Columbine, whom she had befriended during her time at the home.

''I hadn't visited the home for a long, long time and I was told that Sister Alphonso was back in Aberdeen. As I tried to go she walked towards me. That was the first meeting since I left the home. It was like spiralling back in time. It was flashing through my head, all the bad things, everything that went on, it all came back.''

Mrs Cusiter said that Sister Alphonso asked if she remembered anything about her childhood at Nazareth House and when Mrs Cusiter said ''everything'' the nun turned grey and said she was ''only following orders''.

During yesterday's cross-examination she agreed she was suing Nazareth House for #150,000, but said the figure had been decided by her lawyer and that the money was not important. She said she had declined offers of payment for her story from newspapers A claim for #10,000 from the Criminal Injuries Compensation Board had also been lodged by her solicitor on her behalf but she said: ''I never asked for compensation. I would not put myself through this for money, baring my soul.''

The trial continues.