TWO prisoners carried out a "cold-blooded killing" of another inmate in his cell at a top security Worcestershire prison because they both believed he was evil, a court heard.

Gary Lindley and Billy White tried to break Brett Rogers' neck and then suffocated him to "free him from the darkness" they saw in him, Worcester Crown Court heard.

After he was dead, 42-year-old Lindley, a Muslim, and White, a 24-year-old Catholic, said a prayer to "exorcise the demon," Judge Robert Juckes, QC, said in his sentencing remarks.

It was the third killing at Long Lartin prison, near Evesham, in the last two years, he said.

Both men pleaded guilty to murder and appeared for sentence together from separate prisons in a split-screen video link.

White, who was serving a life sentence for murder, was given a full life term, meaning he is unlikely ever to be freed.

Lindley, who was considered dangerous and was already serving an indeterminate sentence for an attempted armed robbery, was given a life sentence with a minimum of 17 years and six months.

The court heard the two men shared the same wing as 25-year-old Rogers, a double murderer.

They decided they were of a like mind and that they would kill him a week before CCTV showed them going into his cell at 11.03am on June 7 this year.

They smoked cannabis with him and then overpowered him, pulling him from his chair and trying to strangle him and break his neck before Lindley put a pillow over his face to suffocate him.

White said in his confession he "had dealt in darkness all his life" and he had never seen anyone with such darkness as he had seen in Rogers' eyes. He said wanted to free him from the darkness.

Lindley said he had been "ordered by the Lord My God to free Brett Rogers."

"They both believed he was particularly evil," Judge Juckes said. He said a letter from Rogers' father showed their belief was ill-founded and he was a vulnerable man.

"This was a particularly cold-blooded killing that took some time in the execution," the judge said. "It was a killing at a high security prison. This is the third killing in the last two years."

He said it had been followed immediately by a confession, which he had taken into account for the sentencing.

Though both men were motivated by religion, he had decided it was not in furtherance of a religious cause.

"They did not pick on him because of his religious beliefs but because of what they had come to believe about him," he said. Both were equally responsible for the "cruel" killing, he said.

Lindley, he said, had already been considered a dangerous man by the judge who gave him his current sentence.

White, he said, was only 24 but he had now committed his second offence of murder and had shown a high level of dangerousness that had to be met by a full life term.