A medium at a spiritualist church has appeared in court accused of engaging in sexual activity with a mentally disabled man.

The medium, who lives in Tooting, took part in oral sex and masturbation with a man in his early 20s with Asperger's syndrome in October 2006, it is alleged.

Giving evidence at Kingston Crown Court on Friday, the man’s mother said she met the medium five years ago at church and had grown to trust him.

She said: “We went to see him once or twice a week, not just on spiritual matters but to talk things through, to feel better about myself.”

She said her son would sometimes get become angry and visit the man’s house for help and advice, staying over three times to cook and help trim hedges.

But he later confessed to her he had shared a bed with the medium and his boyfriend for a massage and he had oral sex in the man’s car.

His mother said: “He seemed quite calm - he was embarrassed. I was shocked. We sat and chatted. He told me everything about what happened.”

The court heard how the medium claimed to connect the living and the dead at the church, which has an “unusual” approach to God.

She added: “Some people have different approaches to what we call God. We have many different ways of relating to what we call God. We use the word ‘spirit’ because it is in us.”

David Cotson, consultant specialist at South West London and St George’s Mental Health NHS Trust, told the court the alleged victim’s disorder made it difficult for him to understand social cues.

Asperger’s syndrome, a form of autism, often renders sufferers unable to understand any sexual advances unless they are put in very plain words.

He added that the man would not have had time to process any unexpected sexual advance and was therefore incapable of giving his consent to such.

The court was also told that the alleged victim’s Asperger’s syndrome was no reason to doubt his evidence.

The defendant denies a charge of sexual activity with a mentally disabled person impeding choice.

The trial continues.