A Dublin teenager who launched an horrific and unprovoked attack on a young man he'd never met has been sentenced to five and a half years in prison.

Luke Dunne (21) of Sheepmore Crescent, Clonsilla, Dublin pleaded guilty at Dublin Circuit Court to assault causing serious harm at Fortlawn Park, Blanchardstown on June 9th, 2012.

The court heard that Joseph Nolan (24) suffered a life-threatening skull fracture and a clot in his brain when he was assaulted by Dunne and a gang of men in a random attack following a house-party.

Mr Nolan was left lying on the ground unconscious and choking on his own blood, with his left ear hanging off and almost torn in two.

Judge Mary Ellen Ring suspended the final 12 months of the sentence saying that Dunne’s admissions on arrest meant that at least one person had been prosecuted for the attack.

She said Dunne, who is the only person to have admitted the crime and has no previous convictions, was being given “greater than normal credit” to encourage such future co-operation.

She said the admissions relieved Mr Nolan of the extra trauma of having to come to court.

In a victim impact report read out on his behalf, Mr Nolan said every aspect of his life has been affected by the assault.

He suffers palsy and nerve damage in the left side of his face and has had severe loss of hearing in one ear, meaning he can no longer work as a DJ.

Mr Nolan said he didn't leave home for five months after he was attacked and found it difficult to return to work. He said his family did not know if he would pull through and his relationship with his girlfriend broke up.

The court heard that Dunne kicked and stamped Mr Nolan repeatedly in the face and body as he lay on the ground. He also punched him at least ten times in the face.

Dunne admitted his role to gardaí after the assault and said he didn't know why he attacked Mr Nolan.

“I got into a rage and just concentrated on my target and blanked everything and everyone else out,” he said.

Garda Pamela Leyden told Gerardine Small BL, prosecuting, that the victim had been sitting in his car talking with some friends shortly after leaving a party at 6am.

A group of four or five youths approached them and one of them tried to open the door, but Mr Nolan locked the car doors.

He tried to reverse but two of the men blocked the passage, while another threw a bottle smashing the driver's window and hitting his face.

Mr Nolan got out of the car and was pursued by the men who hit him across the face with something hard, knocked him to the ground and kicked him in the stomach.

He blacked out while he was getting kicked and woke up in a garden with an ambulance beside him.

Dunne and the victim's friends described Mr Nolan lying unconscious surrounded by broken glass with blood all over his face, choking on his own blood. Gardaí were called and found Mr Nolan's car burnt out in nearby Sheepmore Crescent.

Dunne was arrested and admitted throwing a bottle at the driver's window and attacking Mr Nolan. He said he had drunk beer, cider, whiskey and vodka and taken two ecstasy tablets after the assault.

Caroline Biggs SC, defending, said her client had immediately accepted his involvement and named two others involved, one of whom was stabbed to death nine days later.

She said Dunne was extremely remorseful, shocked, disgusted and ashamed of his own behaviour.

“I'm so sorry, I wish I could turn time back,” he told gardaí.

Dunne had been addicted to “everything from hash, to benzos, to crack cocaine” but was now drug-free and engaging in counselling.

The court heard that Dunne's upbringing was a “catalogue of misery” where his job as a child was to throw needles and dirty spoons over the wall of the Ballymun flats for his drug addict mother, who died prematurely from a bad batch of heroin.

A medical report said Dunne had two personality disorders, a history of impulsivity and difficulty controlling his anger.

A drugs counsellor said Dunne was the youngest ever graduate from their Rehab programme and had worked hard to turn his life around.