A noted writer of children's books was secretly grooming young fans for rape and sexual assault at the height of his fame in the 1960s, Teesside crown court was told yesterday.

William Mayne, now 76, assaulted them at the same time as using them for characters in his best-selling retellings of Arthurian legends, one of the alleged victims told the jury.

Mr Mayne, who is described in the Oxford Companion to Children's Literature as an outstanding 20th-century author, and won the 1993 Guardian Children's Fiction Award with Low Tide, denies twice raping one girl aged under 13, and 13 counts of indecent assault involving seven other girls.

The court was told that he invited young fans to his three homes in London and Yorkshire, took them for rides in his Bentley, and told them that he knew "what girls wanted".

A woman now in her 50s said the assaults developed subtly from "romping" sessions. She told Judge David Bryant that other girls, awestruck by Mr Mayne's fame and skill as a storyteller, were present during the attacks, which began when she was eight.

"We would be romping, wrestling, and I would climb all over him. I used him as a play thing," she said.

But the writer then began the series of assaults, culminating in a rape, between 1960 and 1965.

"He was always behind me, never face on, he never looked at me: there was never eye contact. It was so horrific, so unpleasant, so disgusting, so abhorrent," she said.

"But it was part of the grooming to think it was normal. He was saying this was what we wanted. It is what girls want. The message we got was that he was only doing what we wanted."

She said she had spent several summer holidays at Mr Mayne's home in the North Yorkshire village of Thornton Rust, travelling from London with her family's approval. He had given her nicknames and she had liked him, as well as being entranced by his books.

"I know that sounds incredible," she told the jury, "but I liked our conversations and the attention I got. When other girls were assaulted, I tried to ignore it. It would be happening and I would glance at it and look away."

A second woman said Mr Mayne had reminded her of his assaults shortly before she went to university. "He said to me: 'You know the things I would do to you - I only did because you needed it.'"

The hearing continues.