The survey, the first of its kind, was presented to the British Psychological Society's annual conference in Edinburgh. The society said that it contradicted the claim that such memories were usually caused by the suggestion of the therapists themselves.
The British False Memory Society, however, which represents parents who say they have been wrongly accused, immediately attacked it as unscientific and hearsay evidence.
The question of whether forgotten memories of childhood sexual abuse (usually by family members) can be brought back with the aid of therapy has been bitterly contested ever since the first cases emerged in the United States over the past decade. The idea of repressing memories began with Sigmund Freud who believed humans could remove unacceptable knowledge to the subconscious.
However, many accused parents claim their family lives have been destroyed by fantasies planted by unscrupulous therapists in their children's minds - and the courts have given them backing. In one case, Gary Ramona, a Californian business executive, won pounds 335,000 compensation after his daughter who was undergoing regression therapy accused him of rape.
Those who say they have been abused, on the other hand, argue that if it is possible for war victims to block out horrific events, why should this not be true of sexual abuse?
The report, by Dr Bernice Andrews, chartered psychologist and senior lecturer at Royal Holloway College, University of London, covered 108 practising psychologists, who had nearly 700 clients with recovered memories between them, and who spoke in detail about 236 cases.
The BPS yesterday suggested that three of its findings gave credence to the idea of memories recovered in therapy. The first was that in a third of the cases studied, the patients had started to recover their memories before speaking to a therapist.
The second was that not all memories were about sex abuse - more than a third involved other incidents, such as cruelty.
The third, said the BPS, was that "there was corroborating evidence in 41 per cent of cases."
However the study admits that 41 per cent is the figure for patients who claimed there was such evidence. Only in 3 per cent of the cases, the survey says, had the therapists seen the alleged evidence for themselves.
"Why has third-party hearsay evidence, collected from the very people who might be causing the problem, been given such an unwarranted accolade?" said Roger Scotford, director of the British False Memory Society.
Dr Andrews replied: "If these collaborative reports are not valid, what is going on? Are they not only falsely believing they are abused, but also fantasising about collaborative evidence?"
One psychologist's client claimed to have recovered a memory of being abducted by aliens. "It is likely that some of the memories are false," said Dr Andrews. "However, it is very likely that many of them do correspond to actual events. It is important that popular claims about recovered memories being true or false are not exaggerated but are evaluated in the light of emerging scientific evidence."
The report was welcomed by the Children's Society and the NSPCC. Bob Lewis, president of the Association of Directors of Social Services, said: "Anything that helps to give clearer understanding of this issue is to be welcomed ... there is a danger if you reject some people's accounts you can do a great deal of harm because you fail to accept what they have been through."
Accused and alone
IT IS three years since Joe and Sheila have seen their only daughter or their grandchildren. Their daughter first went for counselling after she suffered post-natal depression following the birth of her second child. She was training to be a nurse and she and her husband had considerable financial restraints. It was a difficult time.
After five years of therapy she began to accuse those around her of abuse - culminating in accusations against her parents. Her husband came round to tell them. "I was horrified. I just couldn't believe it. I immediately thought she must be mentally ill," said Sheila. "I thought 'Is this real? Am I awake?' We had been so close." "Not a day went past when she didn't pop in for a coffee," added Joe.
Sheila's mother has also been cut off by her granddaughter so she cannot see her great grandchildren. Police and social services investigated the allegations, but, said the couple, found no evidence of abuse. The family are now considering suing their daughter's therapist.
"I can't think of anything worse," said Sheila. "It's the end of the family. We are virtually on our own." "You can do nothing if you are falsely accused," said Joe. "No one wants to know."
The jigsaw completed
"IT'S like holding the pieces of a jigsaw puzzle apart," is the way Carol describes her partial amnesia.
She had never fully forgotten that she had been abused by her father but it took a series of triggers before her full memories returned.
She could remember vague parts, but more information came back after she had a child and refused to let her father near him and her sister Emma - also abused - attempted suicide.
For the first time the subject could be broached, but then her sister could not cope and shut herself off from the family. It took another decade before they could speak freely to each other. It was when their father emigrated that the sisters felt free to remember.
Both sisters recovered memory before going into therapy and Carol stresses it did not involve hypnosis. Remembering was slow and painful. "You don't just get your memories back and think 'Yes, that's what happened,' you test it out. Fragments gradually began to make sense."
The sisters wrote to their father confronting him with their allegations. He has since admitted that abuse went on inside and outside the family, says Carol.
Carol says that those who recover memories do not do so rashly, but cautiously. "They are not simple. You have to realise that how you saw the world at the age of six or nine is different and you have to try to get through to that."