A sentence hearing in the case of a teenager, who has pleaded guilty to attempted murder, has been adjourned to allow his defence counsel consider a judgment by the Supreme Court yesterday.

The Supreme Court ruled that statements taken from suspects while in custody may no longer be used as evidence against them if legal advice has been requested and not yet obtained when the statements are made.

Tadhg Costello, 18, of Richmond Hill, Monkstown, admitted attempting to murder 17-year-old Josh Leahy.

The case has been put back for two weeks.

Mr Costello first denied attempting to murder the teenager on 31 May 2012, but on the fifth day of his trial he changed his plea to guilty.

During the trial, Mr Leahy gave evidence that he and two friends were attacked after leaving a nightclub after they met a group of eight people who started shouting at them near the Powerscourt Town House Centre.

He said one of the group had a knife and was waving it at them.

Mr Leahy said he later discovered he had been stabbed six times in the back.

He suffered a collapsed lung and had to have a chest drain inserted at St James's Hospital.

One of the victim's friends also gave evidence that Mr Costello was holding a knife that night and facing him.

He later pointed him out to gardaí on St Stephen's Green where the group was waiting to get a taxi.

Garda Damien Beakey also testified that he saw Mr Costello throw a shiny object behind rails on St Stephen's Green. The garda said he got over the rails and recovered a knife.

Mr Costello changed his plea to guilty during his trial following a decision by the judge on foot of two days of legal argument over the admissibility of the garda recordings of his interviews.

He was due to be sentenced this morning.

However, his defence counsel, Damien Colgan, said he may need to address the court in light of the Supreme Court judgment.

Senior counsel Paul Byrnes said a victim impact report has been prepared and the victim and his mother were in court.

Mr Justice Paul Butler said he had received a very comprehensive probation report on the accused and what it says about the future caused him some concern.

However, he said the defence needs time to consider the Supreme Court judgment and he adjourned the case until 21 March.