OddsFrontTwo scientific experts leave Lucy Letby's defence team over disputed arguments
The researchers still question the insulin evidence in two convictions but say they cannot support other scientific claims advanced on Letby's behalf.
Experts withdraw from the review effort
Helen Shannon, a British chemical-engineering specialist, and Geoff Chase, a New Zealand-based professor of bioengineering, withdrew from Lucy Letby's defence team on September 14. Their departure is significant because they had helped produce a 100-page report questioning the insulin evidence used in two attempted-murder convictions. The experts said they continued to stand by their own assessment of those cases while rejecting other arguments advanced by the defence.
A dispute inside the scientific challenge
Shannon and Chase said some of the additional claims were incompatible with the available evidence, established physiology and defensible scientific practice. Their position does not amount to an endorsement of the prosecution's insulin case: they continue to consider deliberate poisoning very unlikely. Instead, the split concerns how the wider challenge is being constructed and whether associating multiple inconsistent theories could undermine its credibility before the miscarriage-of-justice review body.
The defence says its case remains broad
Letby's barrister, Mark McDonald, responded that experts in insulin, endocrinology and laboratory medicine continue to support challenges to the trial evidence. He said the application does not depend on a single specialist. The Criminal Cases Review Commission is considering a dossier submitted on Letby's behalf, but has not announced whether it will refer any conviction back to the Court of Appeal.
Convictions and official scrutiny
Letby is serving 15 whole-life orders after two trials found her guilty of murdering seven babies and attempting to murder seven others at the Countess of Chester Hospital, with two attempts involving one victim. The government's terms for the Thirlwall Inquiry cover the families' experiences, the conduct of hospital personnel, management responses to clinicians' concerns and the effectiveness of NHS governance and external regulation.
What the departure changes
The experts' withdrawal does not itself alter any conviction, sentence or pending legal decision. Its immediate effect is to expose a substantive disagreement within the team seeking review. Attention now turns to how the remaining defence experts reconcile their theories, what weight the commission gives the insulin material and how the Thirlwall Inquiry's findings affect broader hospital-safety reforms. Those processes remain legally and institutionally separate from one another.