LUCY LETBY CASE FACES FRESH TURMOIL AS NEW INSULIN EVIDENCE PUTS KEY PROSECUTION CLAIMS UNDER SCRUTINY
LUCY LETBY CASE FACES FRESH TURMOIL AS NEW INSULIN EVIDENCE PUTS KEY PROSECUTION CLAIMS UNDER SCRUTINY
The Lucy Letby case is facing renewed scrutiny after new medical research challenged a central piece of evidence used to convict the former neonatal nurse — but one crucial legal fact could determine whether any of those challenges actually reach an appeal court.
Letby remains imprisoned after being convicted of murdering seven babies and attempting to murder seven others. Her convictions have not been overturned.
NEW RESEARCH CHALLENGES THE INSULIN EVIDENCE
The most significant new development concerns the cases involving two babies whom prosecutors said were deliberately poisoned with insulin.
At trial, unusually high insulin readings were presented as evidence that the babies had received insulin. New research, however, has prompted experts to question whether abnormal insulin levels in premature infants can always be interpreted as proof of deliberate administration.
Professor Geoff Chase, an expert in insulin physiology in premature babies, has argued that infection and other physiological factors can produce unusually high insulin-related readings.
A 100-page report submitted to the Criminal Cases Review Commission in July 2026 by consultant neonatologist Neil Aiton and statistician Hilde Wilkinson-Herbots also reportedly challenges aspects of the evidence given by prosecution expert Professor Peter Hindmarsh.
BUT THIS DOES NOT MEAN THE CONVICTIONS HAVE COLLAPSED
That is the critical legal distinction.
The new reports and expert opinions may provide material for Letby’s lawyers to argue that her convictions are unsafe, but no court has yet ruled that the insulin evidence was wrong or that Letby was wrongly convicted.
The Court of Appeal previously rejected her attempt to challenge her convictions in 2024.
Her legal team subsequently submitted a new application to the Criminal Cases Review Commission (CCRC).
And this is where the story takes an important turn.
THE CCRC HAS NOT CLEARED HER — AND HAS NOT REJECTED HER
The CCRC confirmed that it received Letby’s application in February 2025.
The commission is an independent body responsible for investigating alleged miscarriages of justice in England, Wales and Northern Ireland.
But in a statement published in February 2026, CCRC chair Helen Pitcher made clear that the review was still ongoing and pushed back against speculation about its progress.
In other words, the CCRC has not announced that Letby’s convictions are unsafe.
It has also not announced that it will refer the case back to the Court of Appeal.
THAT IS THE LEGAL DETAIL THAT CHANGES EVERYTHING
Even if new experts believe the original medical interpretation was seriously flawed, the CCRC must determine whether the new material provides a realistic possibility that the convictions would not be upheld if they were reconsidered by an appeal court.
Until that happens, Letby’s convictions remain legally valid.
SEPARATE INVESTIGATION INTO HOSPITAL FAILURES
The controversy has also been complicated by a separate investigation into possible failures at the Countess of Chester Hospital.
Three former senior hospital figures were arrested in 2025 on suspicion of gross negligence manslaughter as part of that investigation. No charges have been announced against them.
The investigation is separate from Letby’s criminal convictions and does not itself establish that the babies’ deaths were caused by hospital failures.
Meanwhile, the Thirlwall Inquiry continues examining what happened at the hospital and the implications of the Letby case.
SO COULD THE CASE REALLY BE OVERTURNED?
It is possible, but it has not happened.
The new medical evidence could become highly significant if the CCRC concludes that it creates a real possibility of a different outcome at appeal.
But there are several legal steps still to come.
For now, the facts are:
Letby remains convicted and imprisoned.
New experts are challenging important aspects of the medical evidence.
A substantial new report has been submitted to the CCRC.
The CCRC is still reviewing the case.
No decision has yet been announced to send the convictions back to the Court of Appeal.
The medical debate may be intensifying — but the courtroom battle is not over yet.
The biggest question is no longer simply whether experts disagree with the original interpretation of the insulin evidence.
It is whether that new evidence is strong enough to convince the CCRC that the convictions should be reconsidered by the Court of Appeal.
Until that decision is made, Lucy Letby’s convictions remain in force.
