Soham killer Ian Huntley suffered serious injuries after he was attacked with a metal bar in a workshop at a maximum security jail.
Durham Constabulary said a prisoner, understood to be Huntley, was assaulted on Thursday morning at HMP Frankland near Durham before being rushed to an unnamed hospital.
A force spokesman said: “Police were alerted to an assault which had taken place within HMP Frankland in Durham this morning.
“A male prisoner suffered serious injuries during the incident and was transported to hospital.
“A police investigation is now under way into the circumstances of the incident and detectives are liaising with staff at the prison.”
The Sun, which first reported the attack, said the 52-year-old was knocked unconscious with a metal pole and quoted a source saying his condition was “touch and go”.
The Press Association understood the attack took place in a prison workshop and that Huntley was left in a pool of blood.
This attack was the latest attempt on Huntley’s life and he was thought to have been kept under close observation to prevent similar attacks.
Former caretaker Huntley killed 10-year-olds Holly Wells and Jessica Chapman after they left a family barbecue to buy sweets in Soham, Cambridgeshire, on August 4 2002, then dumped their bodies in a ditch.
He is serving a life sentence, with a recommendation that he must serve at least 40 years for the murders.
A Prison Service spokesperson said: “A prisoner is receiving treatment after an incident at HMP Frankland on Thursday morning.
“It would be inappropriate to comment further while police investigate.”
A North East Ambulance Service spokesperson said: “We dispatched two ambulance crews to the scene and requested support from the Great North Air Ambulance Service.
“One patient was transported to hospital by road.”
Robber Damien Fowkes slashed Huntley with a home-made weapon in 2010, causing a “severe gaping cut to the left side of his neck”.
The wound was 7in (18cm) long and required 21 stitches.
Fowkes asked a prison officer: “Is he dead? I hope so.”
He described Huntley as a “notorious child killer, both inside prison and in society in general”.
Manchester Arena bomb plotter Hashem Abedi is accused of carrying out “terrorist” attacks on prison officers at the maximum security jail with hot cooking oil and makeshift weapons.
He denies three counts of attempted murder after four prison officers were injured on April 12.
Former Lostprophets frontman Ian Watkins died after an alleged attack last October at HMP Wakefield, where he was serving a 29-year sentence for child sexual offences.
On Monday, Killamarsh killer Damien Bendall was handed another life sentence after he admitted the attempted murder of another Frankland inmate whom he attacked with a claw hammer in a prison workshop.
A prison officer who witnessed that attack thought Bendall, who murdered his partner and three children with a hammer and is now serving a whole life tariff, had killed his victim, but he survived.
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