The 52-year-old was seriously injured in the attack that happened in a workshop at HMP Frankland in Durham on Thursday morning.

Ian Huntley is currently serving a life sentence in prison (Image: Archant)

A spokesman for Durham Constabulary said he remains in a serious condition following treatment for head injuries.

He added: "Police forensic teams have examined the scene of the attack throughout the day to gather evidence.

"A suspect, a male prisoner in his mid-40s, has been identified by officers investigating the incident.

"He has not been arrested at this stage but remains in detention within the prison."

Huntley is reported to have been hit six times.

The Sun said the killer was knocked unconscious with a metal pole and quoted a source saying his condition was “touch and go”.

According to the paper, a man shouted, "I've done it, I've done it," after the 52-year-old was hit six times.

What is Ian Huntley serving a life prison sentence for?

Huntley is serving a life prison sentence for the murder of 10-year-olds Holly Wells and Jessica Chapman in 2002.

He claimed during his trial at the Old Bailey in 2003 that the girls, wearing their Manchester United shirts, went inside his house because Holly had a nosebleed.

The bodies of Holly Wells (left) and her best friend, Jessica Chapman, were found in Suffolk (Image: PA)

Huntley, now 52, said in his testimony that Holly drowned in the bath and that he killed Jessica as he tried to silence her screams, but jurors concluded he was lying.

The judge, Mr Justice Moses, told Huntley: “You are the only person who knows how you murdered them.”

The girls’ bodies had been found in a ditch near an airbase at Mildenhall in Suffolk after a two-week search.

Huntley’s girlfriend, Maxine Carr, who was a teaching assistant at the girls’ school, served 21 months for perverting the course of justice for giving Huntley a false alibi.

She is now living under a new identity.

© Eastern Daily Press