The parents of two brothers whose "toxic" upbringing led them to torture two innocent children face prosecution for neglect and child abuse, police revealed last night.

The brothers were given an indeterminate sentence and must be detained for a minimum of five years for the prolonged sadistic attack in Edlington, near Doncaster, last April. They are considered to pose such a high risk to the public that they may never be released. One is thought to be in danger of becoming a psychopath.

The judge said that the attack was carried out with "chilling detachment" by boys aged 10 and 11 whose tools of choice were "aggression, extreme violence and sexual degradation".

Doncaster Council issued an unqualified apology to the families of their victims - who are still traumatised and will be physically scarred for life - after a damning report revealed a litany of failings by its social services. A serious case review found that agencies missed 31 opportunities to take action that would have prevented the crime. Only one member of staff has faced any disciplinary action.

David Cameron used the case to back his contention that Britain is in danger of becoming an irresponsible society. Within an hour of the sentence being passed, the Tory leader claimed that the case was symptomatic of levels of social breakdown.

"I don't think it's right every time one of these events take place to say that it is just some isolated incident of evil that we should look away from," he said. "Are we going to do that every time there is a Jamie Bulger or a Baby Peter or a Ben Kinsella or a Gary Newlove? We shouldn't, we should ask what has gone wrong with our society and what we're going to do about it."

Ed Balls, the Children's Secretary, denied that the scandal reflected Britain's problems. He said that it was "hard to comprehend how children could do such terrible things to other innocent children".

Sheffield Crown Court heard that long before the Edlington attack the brothers, two of seven sons of a drug-addicted mother and a drunken, violent father, had carried out numerous attacks on both children and adults.

They were placed with foster parents in Edlington less than a month before they lured two friends, aged 9 and 11, to a secluded location and embarked on a 90-minute orgy of violence. They robbed the boys, told them they were going to kill them, stripped them naked and forced them to perform sex acts on each other. Giggling, they punched and kicked their victims, stamped on their heads and threw bricks and heavy stones at them before trying to strangle them with a metal noose and a clothes line.

A sharpened stick was driven into one boy's arm, penetrating to the bone; a lit cigarette was placed into the wound. The other boy had a ceramic sink dropped on his head. Blinded by blood, lying face down in mud, he eventually begged to be left to die.

Both children have made a remarkable physical recovery but have been left so scarred emotionally that they can barely look each other in the eyes.

Their attackers pleaded guilty to robbery, causing a child to engage in sexual activity and grievous bodily harm with intent and to assaulting a 12-year-old choirboy a week earlier.

Mr Justice Keith said: "This was prolonged, sadistic violence for no reason other than that you got a real kick out of hurting and humiliating them."

Psychiatric reports gave detailed accounts of the boys being physically abused by their father and watching him punch and kick their mother. From the age of 9, the elder boy smoked cannabis at home, drank alcohol and watched extremely violent and pornographic DVDs. Psychiatrists said that he appeared to be emotionally detached, desensitised and lacking in empathy towards his victims.

When the brothers were told to leave the court after sentencing, the mother of their younger victim erupted in anger, pounding her fist against the screen separating the public gallery from the boys. "Evil little bastards! You evil little bastards! I hope someone does that to you!" she screamed, before being led from the court.