A senior detective has won £50,000 libel damages from a writer who claimed he had framed an innocent man as the Yorkshire Ripper hoaxer.

Detective Chief Superintendent Chris Gregg had sued 64-year-old Noel O'Gara over four publications on the internet, in an e-mail and in a letter to the effect that John Humble - known as Wearside Jack - was "stitched up" by West Yorkshire Police.

Humble, 52, was jailed for eight years in 2006 on four counts of perverting the course of justice after admitting sending hoax letters and a tape to police and a newspaper that diverted the Ripper inquiry in the 1970s.

O'Gara, of Athlone, County Westmeath, Ireland, had alleged that Det Chief Supt Gregg had improperly interrogated Humble for two days while Humble was drunk, tampered with DNA evidence and blackmailed him into pleading guilty.

Mr Justice King, sitting at London's High Court, said that O'Gara had conducted a "persistent campaign of vilification" against Det Chief Supt Gregg, who is in charge of all major investigations in West Yorkshire.

He entered summary judgment against O'Gara on the basis that he had no real prospect of defending the case, and ordered him to pay the full amount of the claim, which was limited to £50,000, within 12 weeks.

He also imposed an injunction on O'Gara, preventing him from repeating the libels, and ordered him to pay £10,000 in costs within 28 days on account of a bill which, pending full assessment, is estimated to exceed £30,000.

O'Gara, the author of a book entitled The Real Yorkshire Ripper, had claimed that the true murderer was a man who used to work for him in Ireland and was still at large, and it was he who sent the letters and tape.

Kate Wilson, Det Chief Supt Gregg's counsel, described O'Gara as a conspiracy theorist whose beliefs were pure speculation.

Dismissing O'Gara's sole defence of justification, the judge said that he could find nothing which amounted to evidence which would begin to contradict Det Chief Supt Gregg's evidence in support of the proposition that each of the allegations was "indisputably false".

He pointed out that not only did Humble plead guilty in court but continued to admit his guilt and made no complaint about the police investigation into him.

He added: "I have no doubt that these were extremely serious libels on a senior serving police officer. They allege serious misconduct in bringing about the conviction of an innocent man, and were wholly false."

He said they were circulated to a substantial number of people within the population, including media organisations, MPs and Det Chief Supt Gregg's professional colleagues.

"His (O'Gara's) behaviour has aggravated the hurt and distress and injury to feelings suffered by the claimant.

"He chose to assert the defence of truth and he had no evidence to support the allegations.

"There has been no apology. I do not find in his conduct spite, but I do emphasise the fact that this defendant has taken every opportunity available to him in the course of these proceedings to repeat these serious libels."

O'Gara was refused leave to appeal, although he can renew his application directly to the Court of Appeal.

After the judgment, Det Chief Supt Gregg said: "The court judgment speaks for itself." He said that any damages received will be given to charity.