A teenage couple detained for life for the brutal killings of a mother and her daughter are due to find out if they have successfully challenged their ''manifestly excessive'' minimum terms.
The boy and girl, then both 14, had sex, shared a bath and watched vampire-themed films after the murders of dinner lady Elizabeth Edwards, 49, and 13-year-old Katie Edwards in Spalding, Lincolnshire.
Now both 15, the couple were handed minimum terms of 20 years at Nottingham Crown Court last November by Mr Justice Haddon-Cave.
Lawyers representing them at a hearing at the Court of Appeal in London in May urged three judges to find that the sentencing judge was in error when he decided on the terms to impose.
The boy watched the proceedings via video-link as arguments were made on his behalf to Sir Brian Leveson, Mr Justice Blake and Mr Justice Lewis.
As well as ruling on the sentence appeals, the judges will give a decision on whether reporting restrictions currently banning the naming of the teenagers should be maintained or lifted.
When sentencing the pair, believed to be Britain's youngest double killers, Mr Justice Haddon-Cave said the case had ''few parallels in modern criminal history''.
He said they had a ''toxic'' relationship, and acted in a grotesque way after the stabbings.
Mr Justice Haddon-Cave told the teenagers: ''The killings were brutal in the form of executions and both victims, particularly Elizabeth Edwards, must have suffered terribly in the last minutes of their lives.''
The Crown Court heard that the boy, who admitted murder, used a kitchen knife to stab both victims in the neck after attacking them as they slept at their home last April.
His girlfriend, who helped to plan the ''cold, calculated and callous'' killings, denied murder.
She claimed to be suffering an abnormality of mental function which impaired her ability to form rational judgments, but was found guilty after a five-day trial.
During the appeal proceedings, Sir Brian said: ''These are life-changing events for so many people.''
He said the ''shocking events'' took from the victims their ''most precious possession, their lives''.
The killings had also ''damaged, if not destroyed'' the lives of many others.