Breakthrough in UK’s longest miscarriage of justice highlights power of new forensic science

A MAN jailed for a brutal murder 38 years ago has today walked free from court after the Court of Appeal quashed his conviction—offering renewed hope to others claiming wrongful imprisonment, including Pembrokeshire’s most notorious inmate, John Cooper.

Peter Sullivan, now 68, was convicted in 1987 of the rape and murder of 21-year-old barmaid Diane Sindall, who was attacked while walking home from work in Birkenhead. Despite maintaining his innocence throughout, Sullivan spent nearly four decades behind bars—until new forensic testing revealed DNA from an unknown man on preserved crime scene samples.

The Criminal Cases Review Commission (CCRC) referred the case back to the Court of Appeal last year, and today (May 13), judges ruled that the fresh evidence completely undermined the original conviction.

Sullivan’s case is now believed to be the longest-known miscarriage of justice involving a living prisoner in British legal history.

The ruling highlights the growing role that advances in DNA science are playing in overturning unsafe convictions. It also raises serious questions about other historic cases—including that of John Cooper, who is currently serving a whole-life sentence for the 1985 murders of Richard and Helen Thomas in Scoveston Park and the 1989 killings of Gwenda and Peter Dixon near Little Haven.

Cooper’s 2011 conviction relied heavily on DNA and forensic evidence—particularly fibres and trace DNA allegedly linking him to the crime scenes years after the murders occurred. Advances in forensic science were hailed at the time for cracking the cold cases, but serious questions have since been raised about the handling and interpretation of that evidence. Critics argue that crucial items were poorly stored, contaminated, or even cross-referenced between unrelated cases, with incomplete exhibit logs and inconsistencies in how samples were managed. There are also concerns that some forensic results were presented to the jury with greater certainty than the underlying science could justify, potentially prejudicing the verdict.

Cooper’s legal team submitted a detailed appeal dossier to the CCRC in 2023.

The case is now under formal review.

Concerns raised include missing or contaminated forensic samples, questionable police procedures, and the alleged mixing of evidence from unrelated cases.

One of the team supporting cooper in his fight to get his name cleared said: “If there was nothing in it, the case would have been rejected already.”

He added that the Peter Sullivan ruling shows how persistent investigation and modern science can uncover serious flaws in past prosecutions.

While Cooper remains behind bars, the momentum from today’s decision may shift public and legal focus back to the unresolved questions surrounding his case.