The family of James Hanratty - hanged 40 years ago for the notorious A6 murder - have failed in their final attempt to have his name cleared.

A bid to have an appeal heard by the House of Lords - the highest appeal court in the land - was rejected on Thursday by the committee which grants hearings.

Hanratty's conviction was upheld at the Court of Appeal in May when three judges headed by Lord Woolf, the Lord Chief Justice, ruled that DNA evidence established his guilt "beyond doubt".

Valerie Storie: Conviction relied on her memory

The judges decided that the 25-year-old was not wrongly convicted in 1962 of shooting dead scientist Michael Gregsten in Bedfordshire. Hanratty - one of the last people to be executed before the abolition of capital punishment in the UK - had always claimed he was 250 miles away from the scene, in Rhyl, north Wales.

Mr Gregsten's 22-year-old mistress, Valerie Storie, was raped and shot.

She survived but was left paralysed from the waist down.

Since his execution at Bedford Prison, Hanratty's family and supporters have fought to prove that, though a petty crook, he was not a killer.

The victims were shot in a lay-by on the A6

In a statement released on Thursday, the family's solicitors said : "At the conclusion of the hearing in the Court of Appeal, the court agreed that there was a point of law of general public importance, namely the question of whether or not it is permissible for the prosecution to adduce new evidence which is not specifically related to new evidence on behalf of the defence.

"Leave was sought to appeal to the House of Lords in relation to that question but permission was yesterday refused by the Appeal Committee."

At the hearing two months ago, three judges ruled that DNA evidence had established Hanratty's guilt "beyond doubt".

Lord Woolf, the Lord Chief Justice, said: "In our judgment ...the DNA evidence establishes beyond doubt that James Hanratty was the murderer."

"Cover-up"

He added that the DNA evidence "made what was a strong case even stronger".

Reacting angrily to the judgement, Hanratty's brother Michael claimed it was "the last cover-up".

"I waited 40 years to get here thinking I would get justice to have it thrown up in my face," he said.

"This is not just a miscarriage of justice - this is murder."

But Detective Inspector Stewart Trail of the Metropolitan Police, who led the re-examination of evidence, said modern DNA techniques had supported the original verdict.

Michael Hanratty said he had been denied justice

"We hope that today's result will finally draw a line under the speculation which has surrounded this case for nearly 40 years," he said.

"We have carried out a full and thorough investigation which has served only to reinforce the original trial verdict."

James Hanratty was convicted of murdering scientist Michael Gregsten on the A6 in Bedfordshire by shooting him twice in the head.

Mr Gregsten's girlfriend Valerie Storie was raped, shot five times and left for dead - she survived but was paralysed from the waist down.

Contaminated

Hanratty's family insisted he was the victim of a "distorted and fatally flawed trial".

They claimed that DNA evidence linking him to the crime may have been contaminated at the time of the original trial.

In April, Lord Chief Justice Woolf, Lord Justice Mantell and Mr Justice Leveson began to re-examine the safety of the 1962 conviction.

At the Appeal Court, barrister Michael Mansfield QC for Hanratty said the "distortion" of the original trial process was "in large measure" due to the actions of the senior police officer, who has since died, in covering-up evidence in several key areas.

Lay-by

It was alleged at the time that Hanratty came across the 36-year-old victim, Mr Gregsten and his 22-year-old girlfriend, Valerie Storie, inside a parked Morris Minor in August 1961.

They were confronted by a man with a gun who ordered them to drive to a remote lay-by, where Mr Gregsten was shot dead and Ms Storey was raped.

Hanratty was arrested, tried and convicted for murder.

The jury did not believe his story that he was in Rhyl at the time of the attack - despite the landlady of a B&B backing his claim.

In the years after his execution, numerous witnesses have come forward to support that story.

James Hanratty claimed he was in Rhyl

His conviction was based largely on Miss Storie's recollection of the voice of her attacker.

Mr Mansfield, however, argued over the course of the appeal that she saw him for only a few seconds during the six-hour ordeal.

In 1999, the case was referred to the Criminal Cases Review Commission (CCRC), the independent watchdog set up to investigate alleged miscarriages of justice.

After carrying out its own investigation, it sent the case to the Court of Appeal.

But the case took another twist when DNA samples were taken from members of Hanratty's family.

They were checked against samples found on Miss Storie's underwear and a handkerchief wrapped around the murder weapon.

The results showed there was a 2.5 million to one chance that the samples came from someone other than Hanratty.

In March 2001, DNA sample extracted from Hanratty's exhumed body was matched by forensic experts to two samples from the crime scene.

The family believed that the DNA sample could have been contaminated.

Hanratty protested his innocence until his death. On the eve of his execution, he told his family: "I'm dying tomorrow but I'm innocent. Clear my name."