The first person in the world to be convicted on the basis of DNA evidence has been given permission to challenge his sentence.
Colin Pitchfork, 48, was jailed for life in 1988 for the murder of two schoolgirls in Leicestershire.
He is currently serving a minimum term of 30 years.
Judges at the Appeal Court in London granted Pitchfork permission to appeal after his lawyers claimed the 30 years were "manifestly" excessive.
He wants his sentence reduced to 20 years - meaning he would be eligible to apply for release on parole.
But Appeal Court judges warned they did not think the sentence would be cut when his case was fully considered at a later date.
Pitchfork, a baker, was jailed at Leicester Crown Court after pleading guilty to murder, rape, indecent assault and conspiracy to pervert the course of justice.
Dawn Ashworth (L) and Lynda Mann (R) were killed more than 20 years ago
His first victim was 15-year-old Lynda Mann, of Narborough, who was murdered in 1983.
Three years later he murdered Dawn Ashworth, from Enderby, who was also 15.
Both girls were raped and strangled.
Pitchfork was eventually caught after the world's first mass screening for DNA in which 5,000 men in three villages were asked to volunteer blood or saliva samples.
Lord Justice Stanley Burnton, sitting with two other judges, said: "We do not hold out great hope to the appellant that in the end the period of 30 years, which is a substantial reduction from a whole life tariff, will be reduced by this court."
He said the offences committed by Pitchfork were of the "most serious and terrible kind" but permission was being granted as his case raised "arguable issues."
A second judge, Mr Justice Grigson, said it would be "wholly inappropriate to reduce what I regard as a modest sentence for truly horrific crimes".
Colin Pitchfork is serving a minimum term of 30 years for killing two Leicestershire schoolgirls
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