Daniel Gill, 14, and Robert Fuller, 15, both of Harrogate, North Yorkshire, were found guilty of the attempted murder of Ashley Murray in August but were sentenced at Hull Crown Court in Friday.

The BBC's Paul Murphy reports from Hull

Passing sentence, Judge Arthur Myerson QC described Fuller and Gill as a "serious risk to the public" and warned if they had been adults they would have been facing sentences of 10 years or more.

The judge also took the unusual step of allowing the boys involved to be named, saying the circumstances were exceptionally grave and it was in the public interest for their names to be published.

The victim suffered 18 stab wounds and was left at an isolated beauty spot outside Harrogate.

He was found 40 hours later by a man out walking his dogs and despite suffering appalling injuries recovered enough to testify in court.

Judge Myerson told Fuller and Gill: "From the moment you set out that morning, the death of Ashley Murray was on your minds. When the two of you believed he was dead you tried to put his body in a bin liner."

After reading psychiatric reports the judge accepted they had behavioural difficulties which enabled convicted Harrogate drug dealer, Paul Aurens, at whose home they watched the film, to exercise undue influence over them.

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Their exposure to the film, to drugs, knives and black magic, combined to "blur the line between fantasy and reality" and between "right and wrong" for the two boys.

The jury heard during the trial that the two boys attacked their friend only hours after watching part of the horror film Scream.

The 18 certificate film, directed by American horror specialist Wes Craven, features a series of brutal stabbings.

Drawings of the masks worn by the killers in the film and pictures of knives were found in one of the boy's school books.

Ashley told police that the film might have been responsible for making his friends suddenly attack him.

Chance discovery

The victim, who still suffers from some paralysis on his left side, told the trial how he was lured to the beauty spot, Birk Crag, by his friends last January.

He said Gill stabbed him through the cheek and repeatedly in the head with a knife and only stopped when he pretended to be dead.

Fuller was said to have stopped Ashley escaping and to have inflicted a stab wound to his arm.

The injured teenager was only found by chance by a man out walking his dog.

He had 18 stab wounds, a collapsed lung, fractured rib and hypothermia.

One of the stab wounds missed the largest blood vessel in his brain by a single millimetre.

Both of the attackers had pleaded not guilty to attempted murder.

'Wicked influence'

Fuller blamed his co-accused, saying he had no idea the attack was going to happen. He intends to appeal against the conviction.

Gill denied any involvement whatsoever during the trial and suggested Aurens, who was currently serving five years for drug supplying, might be to blame.

Since the conviction Mr Roger Keen QC, for the defence, said Gill now admitted his part in the attack but had confirmed it was "the wicked influence of that evil man" which brought it about.

Mr Keen said Aurens had given Gill drugs and by exposing him to black magic had convinced him that the gods wanted Ashley to die.

"He is now prepared to give a witness statement to the police about this man. No doubt the police would wish to bring this man to justice if at all possible.

During the trial Aurens, who appeared as a witness, denied any involvement but conceded he provided an unhealthy atmosphere when boys called round at his home in Wellfield Court, Harrogate.

Parents' anger

In a statement after the trial, a spokesman for Ashley's parents said: "No words can describe the anger and disgust that we feel not only for the two boys responsible but also the evil influence by others.

"We must now focus our efforts on our son's continued recovery, both physical and psychological. We hope that one day he will recover from the paralysis to his left side which will enable him to live a normal life."