A Limerick man who carried out an unprovoked attack on a schoolboy, leaving him with permanent brain damage is challenging his 15 year jail sentence.

The accused from Dooradoyle was a teenager in care of the Health Service Executive (HSE) when he punched, kicked and stamped on the 16-year-old boy's head as he waited for his mother at a service station in Corbally, Co. Clare in July 2010.

CCTV footage of the almost five-minute, frenzied attack shows the accused inflicting 65 kicks and stamps to the schoolboy's head, which continued long after the boy lay motionless on the ground.

The accused wrongly believed the teenager had been involved in having his friend imprisoned for life and after his arrest he told gardai 'I danced over his head'.

An attempted murder charge was dropped when he pleaded guilty to assault causing serious harm and he received a 15 year sentence by a judge who called his crime an 'outrage'.

His lawyers are now appealing the severity of the prison term and have argued the judge was wrong to find the accused man's consumption of drink and drugs was irrelevant as a mitigating factor.

The Court of Criminal Appeal has reserved its decision due to the difficult issues raised by the case.