Three judges sitting at the Court of Appeal reserved judgment on her appeal.

Jack Straw: "Entitled to impose whole life sentence"

Hindley, who has admitted taking part in the torture and murder of four children, was given a life sentence in 1966 with no recommended tariff.

But in 1990 Conservative Home Secretary David Waddington ruled she should stay in jail for the rest of her natural life.

This decision was confirmed by Michael Howard and, last year, the new Home Secretary Jack Straw.

Another 26 prisoners, including serial killers Rose West, Dennis Nilsen and Peter Sutcliffe, have also been told they will never be released.

In December three High Court judges, led by Lord Bingham, upheld Mr Straw's decision but granted leave to appeal to the Court of Appeal.

Rose West has also been told she will never be free

On the last day of the appeal hearing Hindley's lawyer, Edward Fitzgerald QC, said the decision to keep her in jail until she died was flawed because it was based on fears of "a public outcry" if she were freed.

Mr Fitzgerald said the refusal to give the 56-year-old hope of release was inhumane, unfair and unjust.

He said she had been intimidated and corrupted into taking part in the murders by her co-accused Ian Brady.

The court was told the first mention of Hindley's release date was made in 1982 when Lord Lane, then Lord Chief Justice, said she should serve not less than 25 years.

Three years later then Home Secretary Leon Brittan set a minimum term of 30 years for Hindley and 40 for Brady.

But this was subsequently extended to "whole life" by Mr Waddington.

'Let me out'

Mr Fitzgerald asked why the tariff had been extended and said: "Is it because of the intrinsic necessity to increase to whole life in the appellant's case - or is it because the time was getting near when she might be able to say, 'I have done my tariff, I am no longer a risk, let me out'?"

He said Home Office documents showed that in 1985 the Parole Board was considering the "realistic possibility" that Hindley could be released as early as 1990.

Hindley and Brady buried their victims on Saddleworth Moor

Hindley, who was convicted of murdering 10-year-old Lesley Ann Downey and Edward Evans, 17, is currently held at Highpoint prison in Suffolk.

Brady, now 60, was convicted alone of the murder of 12-year-old John Kilbride.

Not until 1987 did the pair admit they had also killed Pauline Reade, 16, and Keith Bennett, 12, and buried their bodies on Saddleworth Moor, overlooking Manchester. Keith's body has never been recovered.

David Pannick QC, for the home secretary, said Mr Straw was legally entitled to decide that notorious killers like Hindley, who were guilty of "wicked and pitiless" acts should be punished "for the rest of their days".

He told the court she had ample opportunity to go to the police and added: "It is not a case where someone was forced to carry out a wicked act with a gun placed to her head."

The judges' ruling will be published later this year.