A woman who beat a partially blind south Wales pensioner to death may be released from prison sooner after a new legal ruling.
Edna Phillips was murdered in her own home
Judges in London on Wednesday overrode Home Secretary David Blunkett's view of the law and ruled him bound to regularly review the length of time juvenile murderers must remain behind bars.
The ruling came in the case of Maria Rossi who was aged 17 when she and another girl Christine Molloy battered 70-year-old, Edna Phillips, to death in her home in Hirwaun, in 1992.
Both were high on drink and drugs at the time.
Rossi, now 28, pleaded guilty to murder at Cardiff Crown Court in 1993 and was ordered to be detained during Her Majesty's pleasure.
In giving the appeal court's decision, the nation's most senior civil judge - the Master of the Rolls, Lord Phillips - criticised the "confused" history of how the legal system has dealt with child murderers.
David Blunkett's view of the law was overruled
Describing the current regime as "almost impenetrable", he urged Parliament to reform the law under which juveniles who kill have been sentenced to be detained "during Her Majesty's pleasure" since 1908.
And he said account should be taken of UK obligations under the United Nations Convention on the Rights of the Child that imprisoning children must only be "a measure of last resort" and custody should be "for the shortest appropriate period".
The court's decision means that Mr Blunkett, despite his denials that he had any legal obligation to do so, must now periodically review the cases of around 200 juvenile murderers.
In April 1999, then Home Secretary Jack Straw, reduced Rossi's sentence from 15 to 13 years and Lord Chief Justice Lord Woolf has since refused to reduce it further.
Her accomplice Molloy was sentenced to 12 years.
Maria Rossi was jailed for murder at Cardiff Crown Court in 1993
Lord Phillips told the appeal court it was Mr Blunkett's case that he had no further obligation to review the tariff.
He maintained that the role of the Lord Chief Justice in tariff reviews and new rules introduced in the wake of the murder in 1993 of Merseyside toddler Jamie Bulger achieved full compliance with the Human Rights Convention.
Lord Phillips, sitting with two other judges, dismissed Mr Blunkett's appeal against an earlier High Court decision in favour of Rossi and Anthony Dudson, who was 16 when he was part of a gang who murdered a teenage girl in Manchester in 1992.
The Home Office was refused leave to appeal further to the House of Lords but is likely to petition the Law Lords directly for an appeal hearing.
The murder of Edna Phillips took place on the Pen-y-Waun estate on 16 July 1992, and left her with at least 35 wounds to her face.
Rossi is now known as Maria Smith.