Hanratty, 25, was executed for the so-called "A6 murder" in one of the most infamous crimes this century. It is understood that his case is to be referred to the Court of Appeal after a fresh investigation into the affair.
The inquiry into the 1961 murder is believed to have concluded that Hanratty should never have been brought to trial and that his conviction was part of a conspiracy, possibly including a police cover-up. He was convicted in 1962 of killing a married man before he raped the victim's lover and repeatedly shot her, leaving her paralysed for life.
The Criminal Cases Review Commission is understood to have decided to refer his case to the Appeal Court - where the conviction is likely to be quashed - after an 18-month inquiry. In all cases so far referred by the commission, the conviction has been quashed or the sentence reduced by the Appeal Court.
As The Independent previously reported, civil servants at the Home Office had reached a similar conclusion in January 1997, but Michael Howard, who was then Home Secretary, decided to sit on what was a potentially embarrassing decision and leave it to the newly formed commission.
Hanratty, a petty burglar, was convicted of abducting Michael Gregsten, 36, and his mistress Valerie Storie, 22, at gunpoint from a cornfield at Taplow, near Maidenhead in Berkshire, in August 1961. The lovers were forced to drive about 60 miles to a lay-by on the A6 near Bedford, known as Dead Man's Hill.
At the end of the two-hour trip Mr Gregsten, a research scientist, was shot dead. Miss Storie was then sexually assaulted before being shot repeatedly at close range. Hanratty was arrested two months later. He was convicted largely on the identification evidence of Miss Storie. Campaigners claim this evidence, which was based largely on her memory of the tone of voice used by her killer, would not now be accepted by a court. There was no scientific evidence.
The investigation by the commission has been headed by Baden Skitt, 57, a former Assistant Commissioner at the Metropolitan Police. Mr Skitt, whose findings were presented to a committee for the final decision, is understood to have concluded that the original investigation was deeply flawed and that much of the "evidence" should never have been used at trial. The commission is expected to make a statement in the next few days.
Michael Hanratty, 59, the brother of James, said last night: "It's been a terrible struggle that has ruined a whole family. You can't explain how it has affected us - it's been devastating.
"The whole case has been a whitewash for years. There have been official inquiries in which people have bent over backwards to cover things up."Reuse content