Sutcliffe murdered 13 women during a killing spree in northern England
Gordon Brown has said it is "very unlikely" Yorkshire Ripper Peter Sutcliffe will be released from jail.
His comments followed a report in the Sun which said doctors at Broadmoor had told the serial killer's lawyers he was no longer dangerous.
The paper said if the justice secretary agreed to downgrade him as low-risk, he could be moved to a medium security prison and eventually released.
Sutcliffe, from Bradford, was jailed in 1981 for murdering 13 women.
Speaking at his monthly news conference, Mr Brown said it was "very unlikely" Sutcliffe would ever be released.
Gordon Brown: 'I don't think he will ever be released'
He said: "Any prisoner held under the Mental Health Act will only be downgraded, as is suggested might happen, if the Mental Health Tribunal, which is independent, is satisfied that it's safe to do so."
"We're not aware of any tribunal being asked for or arranged in relation to this case.
"Obviously the tribunal would consider these issues but in my view it is very unlikely that anything is going to happen that is different from the sentence that has been imposed upon him."
Sutcliffe was given 20 life sentences and told by the judge he would serve a minimum of 30 years for his killings across the north of England.
He was transferred to Broadmoor three years into his sentence after being diagnosed with schizophrenia.
A spokesman for the Ministry of Justice said life sentence prisoners could not be discharged by the Mental Health Tribunal while they were detained under the mental health act.
If a tribunal review found a prisoner's condition no longer justified detention in hospital, he or she would return to prison, he said.
"A life sentence prisoner's release can only be ordered by the Parole Board, and he has no access to the Parole Board while he remains lawfully detained in hospital under the Mental Health Act," he added.
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