Lennon's sister tells of 'disgust' for biography

Family member complains of 'sordid and scurrilous rumours' about ex-Beatle

John Lennon's sister has expressed her disgust at claims in a biography that he was abandoned by his mother and harboured incestuous feelings for her.

At the launch of a new exhibition charting Lennon's early life in his home city of Liverpool timed to coincide with what would have been the Beatle's 68th birthday, Julia Baird said it was time to speak out on behalf of the family.

"John is no longer around to defend himself from some of the bizarre, sordid and downright scurrilous rumours that sadly surround his extraordinary life. It makes me so sad, especially in recent weeks, when all manner of accusations have been flying about," she said.

The publication of Philip Norman's John Lennon: The Life has reignited speculation over the rock icon's early years. Written with the assistance of Yoko Ono and Paul McCartney – both of whom are said to be unhappy at the result – Norman describes how Lennon developed into a lonely and vulnerable teenager after he moved in with his aunt Mimi following the collapse of his mother Julia's marriage to the wayward Alfred "Freddie" Lennon.

The probe into Lennon's psyche is given added weight by the contribution of his therapist, Arthur Janov, as well as the author having been given access to Mimi's private papers and notebooks belonging to the Beatle.

Julia Lennon died in 1958, run over by an off-duty policeman when John was just 17. As well as struggling to come to terms with her death, the young John was haunted by the recollection of having accidentally touched his mother's breast during his adolescence. "I was wondering if I should do anything else," his therapist says he told him. "I always think I should have done it. Presumably she would have allowed it."

Lennon's troubled relationship with his free-spirited mother was evident in much of his work. He described "Help" as "the only honest song I wrote" and "Mother" from his first solo album includes the lament: "Mother, you had me but I never had you." He also recorded the love song "Julia" on The Beatles' LP known as the "White Album".

But according to his half sister, the Lennon family, although unorthodox, was happier than many believe. She tried to set the record straight in a 2007 book, Imagine This but says few wish to hear the truth. "John was removed from our mother, Julia, at the age of five to live with his aunt Mimi. He was not abandoned nor was he unloved – despite what the accepted tale might be. I'd like to take this opportunity to reiterate once more the love our mother Julia had for John and I," Ms Baird said.

"In the short time I had with her, she installed the deep love and spiritual strength which have let me go on and was an inspiration to my brother John. I'm in no doubt that John felt the same."

Julia Lennon was perhaps the defining influence on her son's career, introducing him to the music of Elvis Presley and buying him his first guitar.