Home Secretary Jack Straw has promised changes to the way juveniles are prosecuted after the European Court of Human Rights ruling on the Bulger case.

The Strasbourg judges decided that the killers of Merseyside toddler James Bulger did not receive a fair trial.

They also said former Home Secretary Michael Howard was wrong to intervene in the sentencing of Jon Venables and Robert Thompson, who were 11 when tried at Preston Crown Court in 1993.

Mr Straw told Parliament he accepted the 120-page judgment and would need time to study the implications.

He said: "The real agony is felt by James's parents. They have to endure, and will continue to endure, the profound grief of losing their son."

Mr Straw said the ruling did not exonerate the boys from responsibility for the "appalling murder".

He said the criminal justice system relating to juveniles charged with serious offences such as murder would have to be reformed "as expeditiously as possible". But he did not say what form the reforms would take.

Mr Howard, now an Opposition backbencher, objected in principle to the ruling and said: "We should work to ensure that in future the (European) court operates in a different way and respects the rights of mature democracies with mature systems to decide cases of this kind."

The judges said the trial was not fair because it was held in public, and subject to intensive press coverage. But they stressed the pair had not been treated in an "inhuman and degrading" way.

The judges also awarded costs and expenses of �15,000 to Thompson and �29,000 to Venables.

James's mother, Denise Fergus, said she was very disappointed and added: "The killers have slick lawyers and always get kid glove treatment.

"The British Government should not allow the European Court to dictate how we operate our legal system."

In February 1993 Thompson and Venables abducted James from a busy shopping centre in Bootle, Merseyside, while his mother was distracted, and walked him more than a mile to a railway line.

When they got to the track they poured paint over him, tortured and battered him before leaving him for dead on the line, where he was run over by a goods train.

The pair were identified from CCTV footage and nine months later they went on trial.

The BBC's Legal Affairs Correspondent, Joshua Rozenberg, says the ruling will almost certainly affect the way juveniles accused of serious offences are tried.

He says children will have to be tried in a less formal setting, more like a juvenile court, with judges and lawyers abandoning their robes and wigs as well as much of the legal ritual of the adult courts.

Child law expert Allan Levy QC said it was highly unlikely the case would be retried, considering that the pair may now be free in two years' time.