In a letter to the Home Office, Dr Eric Shepherd, an independent forensic psychologist, strongly criticises the quality of the Merseyside inquiry into the murder, which led to the decision last February by Kenneth Clarke, then Home Secretary, not to reopen the case.
Dr Shepherd was consulted by Merseyside Police during the inquiry and supported the view of other experts, submitted by the lawyers for the four men convicted of the murder, that the confession of involvement by one of the men, Patrick Molloy, was unreliable. After Mr Clarke's decision, Dr Shepherd publicly expressed his surprise that the case was not referred back to the Court of Appeal.
Since then, he has examined the confession on behalf of the solicitor acting for the men, which he says reinforces his stance. He says this is clear from two crucial elements known to Merseyside Police: differences in timings between the statements made by Molloy and the official custody record, and the discrepancies between evidence given by detectives in court and their subsequent accounts to the investigation.
He said yesterday: 'I maintain that either Merseyside Police were negligent in not passing this information on to the Home Office, which clearly they should have done, or that the Home Secretary acted wrongly in not passing it to the Court of Appeal. It is possible that Mr Clarke acted ultra vires in making a judicial decision which he should have referred to the courts.'
The Merseyside inquiry was the seventh to be conducted into suggestions that the men were wrongly convicted of the 1978 murder of a 13- year-old newspaper delivery boy shot when he disturbed burglars at a Staffordshire farmhouse.
Since Mr Clarke's decision, the foreman of the original trial jury has claimed that he believed the men were wrongly convicted because of the influence of the
confession on their deliberations. The confession was given to a detective, now dead, who was a member of the West Midlands Serious Crime Squad when it was disbanded and who was criticised in the Court of Appeal for effectively committing perjury in another case.
Another detective is said to have written down the confession interview while sitting outside the cell. Dr Shepherd believes it is unlikely that he could have done so.
Jim Nichol, solicitor for the three men - Molloy died in prison in 1981 after disowning his confession - said last night: 'This is another important development in the case which is now becoming impossible for the Home Office to sustain.'
Merseyside Police are conducting a further investigation in response to submissions by Mr Nichol and Dr Shepherd. Yesterday a Home Office spokesman said Dr Shepherd's points had been in the original Merseyside submission and the file examined by Mr Clarke: 'The decision not to reopen the case was taken with full knowledge of the discrepancies in the evidence of the police officers and Dr Shepherd's report on the confession.'