May 2026: Thirlwall Inquiry report delayed to at least September 2026 · six-baby inquests relisted to 2027 · CCRC review active · Shoo Lee Panel: no medical evidence of deliberate harm.
Prof. Peter Hindmarsh, Professor of Paediatric Endocrinology at University College London and Consultant Paediatric Endocrinologist at Great Ormond Street Hospital, was presented to the jury as a senior, eminent expert qualified to interpret the Roche Cobas insulin immunoassay results for Babies F and L. His interpretation of the insulin-to-C-peptide ratios as diagnostic of exogenous insulin administration was the principal scientific support for both insulin counts.
On the same day Prof. Hindmarsh began giving evidence at the 2022–2023 Letby trial, the General Medical Council opened a fitness-to-practise investigation into him. A subsequent Medical Practitioners Tribunal Service interim order imposed severe restrictions on his clinical work, stating that he 'may pose a real risk' to members of the public and that the allegations 'may have the potential to impact on his ability to act as an expert witness'. The jury was never told. On 14 November 2024 — after the original trial concluded and after the 2024 Court of Appeal refusal — Hindmarsh removed himself from the GMC register through voluntary erasure, which ended the GMC investigation without any regulatory finding. The post-conviction expert critique argues this non-disclosure to the jury is material because, under Criminal Procedure Rules Part 19, an expert witness owes a primary duty to the court and is obliged to disclose anything that bears on competence, credibility or independence. It is now one of the central grounds in the CCRC submission record on the insulin counts.
"The Medical Practitioners Tribunal Service concluded that the allegations against Professor Hindmarsh may have the potential to impact on his ability to act as an expert witness. The jury was never told." — Patient Safety Learning hub summary, 2025
Prof. Peter Hindmarsh's expert evidence on the insulin assay results was presented uncontested by any disclosure of the parallel GMC investigation. The Crown's closing relied on his interpretation as the principal scientific underpinning of the two insulin counts.
The Shoo Lee International Expert Panel's medical findings on the insulin counts were reached independently of the GMC issue. The Joint Expert Witness Insulin Report (May 2025) addresses the assay-methodology grounds; the GMC non-disclosure is a separate procedural ground engaging Criminal Procedure Rules Part 19.