David Naughton (19) was extradited from Britain to face charges after the death of Stacey Haugh (16) and Lorna Mahoney (13) on 17 October 2003, when he crashed into a wall in Carrigholt, Co Clare, killing the young Kilkee neighbours.

Last week Judge Con Murphy said that Naughton "was on a campaign of dangerous driving" before he sentenced him to three years in prison at Ennis District Court.

The Sunday Tribune has learned that the EU arrest warrant employed to extradite Naughton contained a major error as it stated that the penalty for dangerous driving causing death "carries a maximum sentence of imprisonment of a term of five years" when the maximum penalty is actually 10 years. Had Naughton been imprisoned for more than five years, he could potentially have argued for a lesser sentence on the basis that the warrant specified, albeit incorrectly, that the maximum penalty was 10 years.

A senior legal source said "there seems to have been a glaring irregularity on this EU arrest warrant. In these matters everything has to be correct so it should not contain any errors.

"I think that if there was an extradition the other way from Ireland to Britain that there would have been more scrutiny of the warrant. However it is important to note that once this man went before the court a new process started."

It is understood that Naughton's counsel, Martin Giblin SC, raised the issue of the error on the EU arrest warrant with Judge Murphy during the case and argued that the maximum penalty that could be imposed on Naughton was five years because of the mistake on the warrant.

The arrest warrant containing the error was signed by High Court Judge Iarfhlaith O'Neill on 12 May last year.

Paul McCutcheon, head of the School of Law at the University of Limerick and an expert in criminal law, said "this error might have been relevant had the court been giving the accused more than five years for the offence.

"You have to ask if any fundamental error of the accused was breached but it is hard to say that there was in this case.

He was before the court on a charge known to the law and he got a sentence that was proportionate to the offence."

When contacted by the Sunday Tribune to find out who is accountable for the error and if similar errors are common with EU arrest warrants, nobody from the Office of the Attorney General was available for comment.