When details of their “sadistic torture” on a pair of young boys were read out to the court the two brothers sat emotionless. But today hearing tales of their own “toxic” homelife was apparently too upsetting.

Just a few minutes into his mitigation, as he told the court about regular beatings their father would administer to their mother, Peter Kelson QC was forced to pause as the brothers fidgeted behind him.

First the elder of the defendants, who is 12, was asked if he was okay. Then it became clear it was the youngest of the pair, now 11-years-old, who was in most distress.

His face red, he folded his arms on the desk in front of him and buried his head in them. A social worker gave him a tissue to wipe his tears and then took him crying from the courtroom.

It was behaviour in stark contrast to the impassiveness shown by the pair during the hours it has taken the prosecution to tell the court about their robbery and assault of two boys who were just 11 and nine-years-old.

At times they have mouthed inaudible words and glanced along the table at each other, but on the whole they have looked straight ahead, drinking water and yawning occasionally.

But the reminder of their violent and unconventional upbringing brought a tearful reaction.

In mitigation the judge heard that the boys had a “toxic” homelife. The elder brother, in particular, was beaten by his father and had been drinking alcohol, smoking and taking drugs since he was nine-years-old.

He also used to watch his father’s pornographic DVDs and had also watched horror films including Child’s Play and Saw. The court was also told that the brothers’ elder sibling was in prison.

The court heard details of the brothers’ previous convictions. The older brother has four convictions and a reprimand which date back to August 2007. His offences include trying to steal the handbag of a 65-year-old woman and attacking an eight-year-old boy and his mother.

His brother has one reprimand which was given in March 2009, just weeks before the Edlington attacks, when he punched a 50-year-old woman and headbutted a 53-year-old man.

Earlier the court heard that the brothers told the police had only stopped their assault on their young victims in Edlington after an hour and a half because their arms were sore.

The siblings, aged 10 and 11 at the time, have admitted attacking their victims after luring them away from a playground and are expected to be sentenced today.

Yesterday Sheffield Crown Court was told about what the boys said in police interviews after being arrested following the attacks, which took place in Edlington, south Yorkshire, in April last year.

When asked by officers why he had stopped, the older brother replied: “Cos I’d had enough…I didn’t want to do any more…My arms were aching.”

He was then asked, on a scale of one to 10, how close he thought he and his brother had come to killing their victims. He said eight or nine.

His younger brother, who is now 11, was asked how he felt after the attacks. He replied: “Tired…my arms were hurting.”

The officer asked: “If your arms hadn’t been aching, would you have carried on?”

“Yeah,” he replied.

Handwritten letters from both victims have been handed to the judge telling him the impact the attacks have had on their lives. The elder boy, who is the uncle of the younger victim, says he still has concerns that the defendants will repeat their attack on him, but that his nightmares are less frequent.

The court heard that the younger boy’s behaviour at school has deteriorated and he does not go out as much as he used to.

Nicholas Campbell QC, prosecuting, added: “It is also clear that the experience of these two victims have put a real strain on their relationship. Where they were regularly in each other’s company now that is no longer the case.”

Speaking about the victims’ extended families, Mr Campbell added: “They have their own anxieties and their own feelings of guilt because of what was perpetrated upon their children when they were not there to protect them.”

Earlier in the day, the court had heard how both brothers attempted to pin the blame on each other for the attacks.

The elder brother said that his younger brother was responsible for one of the most serious injuries inflicted – a gaping wound to the arm of the younger victim – and that he had look away, telling police: “I don’t like looking at other people’s blood.”

The older brother also told police of his concern for his victims. He said that at one point, when the victims were covered with a plastic sheet, he had made holes so the boys could breath.

He also said that he had planned to tell his father about what they had done, because he was worried about the older victim in particular, saying: “He’ll freeze to death at night.”

The younger boy told police the attack had nearly made him sick. He told police that he had pleaded with his brother to go back and help the older boy, saying: “It’s tight just leaving him there to die.”

Older brother police interview (extract):

Police Officer: Why have you done all this?

Boy: Don’t know. ‘Cos there were nowt to do.

He said he had been bored and was asked:

PO: What made you stop?

B: ‘Cos I’d had enough, me.

PO: You’d had enough?

B: And I thought it was tight.

PO: What do you mean by you saying ‘I’d had enough’?

B: I didn’t want to do any more.

PO: And why didn’t you want to do it anymore?

B: My arms were aching.

If his arms had not been aching, he said he would have carried on.

Younger brother police interview (extract):

Police Officer: Have you meant to kill them?

Boy: No.

PO: Why did you stop?

B: Erm, he kept screaming, so I stopped it.

He was then told by the police that his brother had said he stopped when his arms got tired.

PO: How were you feeling?

B: What, when I kept hitting ‘em?

PO: Afterwards?

B: Tired…my arms were hurting.

PO: If your arms hadn’t been aching, would you have carried on?