Stone has always denied his involvement in the murders

Intense media interest in the case and the "inherent unreliability" of a witness prejudiced the trial, Stone's barrister Mark McDonald said.

Stone is seeking permission to appeal against his conviction for the 1996 murders in Chillenden, Kent.

Mr Justice Treacy heard the arguments and will decide if he can appeal.

'Pipe confession'

Justice Treacy will now consider if Mr McDonald's comments about an unreliable witness are correct.

The barrister claims the prosecution's witness, Damien Daley, who was in a neighbouring cell when Stone was held on remand and said the accused had confessed to him, was unreliable.

At the trial in 2001, Daley told the jury he had heard a voice coming "through the pipe-work" at Canterbury Prison confessing to the killings.

Josie Russell survived the attack that killed her mother and sister

The prosecution said the voice was Stone's but on Friday Mr McDonald said there was no evidence of this.

He argued the evidence should either have been excluded altogether or the jury should have been given a far stronger warning about the unreliability of Mr Daley's testimony.

Stone was given three life sentences in October 2001 after being convicted of murdering Lin and Megan Russell and attempting to murder Megan's sister Josie.

There was no forensic evidence linking Stone to the attacks on Dr Russell, 45, and her daughters as they walked home from a swimming gala in July 1996.

Stone denied any involvement and said Daley was lying about the confession.

Michael Stone's solicitor Derek Hayward said: "The defendant has maintained his innocence throughout and continues to do so."

Mr Justice Treacy said he would give his decision on whether to grant permission to appeal in writing at a later date.