A former taxi driver's claim that he was the Yorkshire Ripper's first victim is featured in a hard-hitting new book about the serial killer.

John Tomey believes the man who brutally attacked him on the moors above Keighley in 1967 was Peter Sutcliffe.

Almost a decade later Sutcliffe began a reign of terror that left 13 women dead and several others with horrific injuries.

Allegations that the Ripper may have attacked men in the 1960s -- including murdering one -- are revealed in the new book Wicked Beyond Belief.

Investigative writer Michael Bilton's 480-page book reveals new facts about the murders and the massive hunt for the killer.

Police officers and surviving victims spoke for the first time, and forensic evidence, witness statements and autopsy reports were revealed.

Bilton details John Tomey's ordeal as well as attacks in 1975 on Keighley woman Anna Rogulski and Silsden teenager Tracey Browne.

After he was caught in 1981, Sutcliffe told police that the attack on Anna, in an alleyway behind the present Gala Bingo in Alice Street, Keighley, was his first.

The July assault was followed the next month by a brutal attack on 14-year-old Tracey just yards from her home at Upper Hayhills Farm.

In the 1990s Sutcliffe finally admitted attacking Tracey, but continued to deny some other assaults, including those on men.

Bilton argues that if Sutcliffe did kill men as well as women, it exposes his claimed motive -- a "divine mission from God" to kill prostitutes -- as a lie.

This means Sutcliffe could be transferred to maximum security prison rather than his current home in a "comfortable but secure" psychiatric hospital.

Allegations in Bilton's book prompted a Leeds MP to write this month to the Home Secretary, asking him to re-examine Sutcliffe's situation.

The MP, Fabian Hamilton, says the Ripper is "bad, not mad", and it is in the public interest that he is sent to prison.

West Yorkshire Police this week agreed to follow up another of Bilton's claims, that Sutcliffe wore a specific piece of clothing for each murder.

Officers will look for forensic evidence on the pair of home-made green leggings, which tie around the waist and are open at the crotch.

The clothes were ordered to be destroyed after Sutcliffe's trial, but were kept by former Detective Constable Alan Foster.