Anna Wohlin, who discovered 27-year-old Jones in the pool at his farmhouse in Hatfield, Hertfordshire, told Swedish newspaper Expressen that it had taken her 30 years to talk about the night of 3 July, 1969.

"It hurt so much and went so deep. It was as if it had not happened to me," she told the newspaper.

"I was in such shock that I was sick. Then I repressed it - I got married."

A verdict of misadventure was recorded at the inquest into Jones' death, which happened a month after he left the band. It was believed he was under the influence of drink and drugs.

Wohlin, who is 53 and runs a clothes shop in Stockholm, claims builder Frank Thorogood - who is now also dead - killed the guitarist in a row over money.

Inquiries briefly reopened in 1994

Thorogood was working for Jones at the farm at the time. In 1994 police re-opened their inquiries when a recording of an alleged death-bed confession by Thorogood came to light. But the investigation did not progress.

Wohlin insists Jones had stopped using hard drugs and had cut back on his drinking at the time of his death.

She said she wanted to tell her side of the story following her recent divorce. Her book, The Murder of Brian Jones, has just been published.

"I felt I wanted to tell what really happened, mainly for the sake of his son and his closest friends who also believed he died when he was on drugs," she said.

"That wasn't true. I knew what was going on."

On 3 July this year hundreds of Rolling Stones fans from around the world gathered at Jones' grave in Cheltenham, Gloucestershire.

Among them were former Stones drummer Carlo Little, Jones' former girlfriend Pat Andrews and their son Mark, and the band's tour manager Tom Keystone.