Two experts who had previously supported claims of a miscarriage of justice for convicted nurse Lucy Letby have withdrawn their support from her defense team. Helen Shannon, a chemical engineering expert, and Geoff Chase, a professor of bioengineering, stated that they could no longer endorse certain aspects of the defense's arguments due to concerns about scientific credibility and "unresolvable problems."
In a letter to the Criminal Cases Review Commission (CCRC), the experts expressed that while they stand by their assessment that it is "very unlikely" the two babies in question were poisoned with insulin, other arguments being presented by the defense are "inconsistent with the available evidence, science and established physiology."
Shannon and Chase accused Mark McDonald, the barrister leading Letby's appeal, of "placing the long-term interests of Ms Letby at serious, unnecessary and unacceptable risk." They added that these consequences also extend to the families of the babies who died and were injured.
Letby, 36, is currently serving 15 life sentences after being convicted of murdering seven infants and attempting to murder seven others at the Countess of Chester Hospital between June 2015 and June 2016. She has consistently maintained her innocence.
The CCRC is considering a dossier of evidence submitted by an international panel of doctors and scientists, including the report produced by Shannon and Chase, which cast doubt on her convictions. Dr. Shoo Lee, a Canadian neonatologist, led this panel. In February 2025, Dr. Lee stated at a press conference that no murders had been committed and that the babies died of natural causes or due to poor care.
However, the independence of Dr. Lee's panel was questioned in September when it emerged he had written to potential reviewers stating, "We might be her (Letby's) last hope." This prompted some medical professionals to decline participation.
Additionally, McDonald has been reported to the Bar Standards Board following a complaint believed to be related to a leaked letter from his instructing solicitors to a coroner. The letter requested "interested party" status for Letby in inquests into her victims' deaths and reportedly disclosed the babies' identities, causing distress to the families.
In response to the withdrawal of Shannon and Chase, McDonald stated that Letby's innocence case does not "stand or fall on any one expert." He asserted that new evidence from international experts in insulin, endocrinology, and laboratory medicine "fundamentally undermines the scientific evidence relied upon at trial." He added that independent experts from various disciplines have identified significant problems with the scientific basis of the jury's conclusion that the babies were poisoned.
The CCRC, which has been reviewing Letby's convictions for 18 months, declined to comment. A public inquiry into the murders is set to publish its findings, which are expected to highlight missed opportunities for intervention when concerns were raised about a spike in deaths on the neonatal unit in 2015 and 2016. A police investigation into potential corporate manslaughter and gross negligence manslaughter at the hospital is also ongoing.