A convicted murderer who tried to slash the neck of a paedophile prisoner in a frenzied cell attack admitted that he engineered a move to Wakefield prison simply to kill the predator.
Arron Graham, 27, admitted he had "been tracking" sex offender Paul Boardman who had been jailed for abusing children.
Appearing at Leeds Crown Court via video link, Graham, who is already serving a life sentence, "saw an opportunity to seek revenge" when he was granted a move to Wakefield, Dave MacKay for the Crown said.
He purposely befriended Boardman before planning the attack, including studying medical books to find which veins he needed to cut to ensure his death.
He also planned to carry out the murder on a Wednesday when he thought prison guards would be more distracted.
On November 14, 2018, Graham went to Boardman's cell where the victim thought Graham was going to give him a bar of chocolate.
But when his back was turned, Graham grabbed him by the neck and tried to slash his throat with a homemade shank - a razor blade melted onto a toothbrush.
He then forced Boardman to his bed and slashed him again across the forehead.
CCTV played in court showed Boardman then fleeing his cell pursued by Graham, hacking at him before prison officers jumped in.
Boardman suffered deep wounds to his neck and head, but no permanent injuries.
Graham was quick to admit his motive and told officers: “I knew I had missed the artery because there not enough blood. I was disappointed not to kill him."
Admitting attempted murder, the court was told that Graham had 15 convictions for 27 offences including assaults, robbery and then murder in 2014.
He had been part of a gang that killed a man in a revenge attack in Preston, Lancashire.
Graham had received a minimum 29-year sentence for his part in the gruesome death in which the victim was almost decapitated with a knife.
Graham's barrister, Richard Barradell, said in mitigation that his client was still a young man and feels very strongly about the child abuse carried out by Boardman.
During discussions between Mr Barradell and the Judge Andrew Stubbs QC about the possible length of the sentence, Graham interjected by saying: "I don't want to be released."
On sentencing, Judge Stubbs told him: "It was a carefully-planned and determined attempt to take his life, fuelled by your desire for revenge.
"You engineered a move to the same prison after finding him in the system.
"You made frank admissions about your motive. You are plainly dangerous."
He handed Graham another life sentence, to serve at least seven more years after his 29-year sentence for murder has finished.