The Shoo Lee Panel — February 2025 baseline
The Shoo Lee International Expert Panel was convened following the convictions and reported in February 2025. The Panel comprised senior neonatologists, paediatric pathologists, and clinical biochemists drawn from the United Kingdom, Canada, the United States, Australia, and continental Europe. Its remit was to review each of the incident cases independently, assess the evidence presented at trial, and provide case-by-case opinions on whether natural-cause explanations were available.
The Panel’s February 2025 report concluded that, for each incident reviewed, there were one or more natural-cause explanations consistent with the clinical presentation, the post-mortem findings, and the documented medical context. The Panel found that the prosecution’s expert evidence had, in several cases, not adequately considered or excluded available natural-cause differentials, including extreme prematurity complications, infection, necrotising enterocolitis, and resuscitation-related injury.
The Panel’s report was accompanied by a press statement at which Dr Shoo Lee presented the Panel’s collective findings. The Panel was explicit that its conclusions were independent of any legal process and were directed at the scientific question of whether the medical evidence supported the prosecution’s proposed mechanisms of harm.
The Joint Insulin Report — May 2025
In May 2025, a joint report on the insulin evidence relating to Babies F and L was published by a group of clinical biochemists and endocrinologists with expertise in insulin assay methodology. The insulin evidence was central to several of the most serious counts in the prosecution and had been described by the Crown as among its most compelling physical evidence.
The Joint Insulin Report addressed two distinct questions. First, whether the assay methods used to measure insulin levels in the samples from Babies F and L were sufficiently validated for use in a forensic context involving neonatal samples. Second, whether the C-peptide suppression pattern relied upon by the prosecution was, as the Crown alleged, diagnostic of exogenous insulin administration.
According to the report, the assay methodology used had not been validated for neonatal samples, and the reference ranges applied were derived from adult populations. The report further found that C-peptide suppression, while consistent with exogenous insulin administration, is also observed in certain neonatal hypoglycaemic states and in the context of post-mortem sample degradation. The report concluded that the insulin evidence, as presented at trial, overstated the diagnostic certainty of the exogenous- administration finding.
Royal Statistical Society engagement — 2022 to 2024
The Royal Statistical Society’s engagement with the statistical questions predates the verdicts. Its September 2022 report on statistical issues in investigations of suspected medical misconduct set out the risks of co-occurrence evidence — the prosecutor’s fallacy, reference-class problems, and selection effects — in healthcare-serial-killer investigations. In October 2023 the Society wrote to the chair of the Thirlwall Inquiry, and in 2024 it issued a public statement on the statistical aspects of the Letby case acknowledging the concerns raised by its members and the wider statistical community about the shift-attendance evidence.
The roster chart in the peer-reviewed literature — December 2025
On 9 December 2025, Medicine, Science and the Law published “Use of roster charts in the investigation and prosecution of nurses suspected of inflicting deliberate harm on patients” by Prof. John O’Quigley (UCL). The peer-reviewed paper analyses the statistical information contained in the roster chart shown to the jury — including the shift data of the 37 other nurses — and concludes that, from a forensic statistical point of view, the chart should not have been put before jurors.
In June 2026, Prof. Richard Gill published a formal critique of the paper, identifying what he described as serious errors in its statistical modelling — while stating that he strongly agreed with O’Quigley that the roster chart is “fake evidence which should not have been shown to jurors”. The exchange is significant precisely because the two statisticians dispute the modelling details yet agree on the forensic conclusion.
Peer-reviewed insulin research — April 2026
On 29 April 2026 the Journal of Diabetes Science and Technology published a peer-reviewed article by Prof. Geoff Chase, an insulin modelling expert, and Helen Shannon, a chemical engineer. The paper argues that around four in ten preterm babies have high insulin readings, and that babies are often born with antibodies that bind to insulin — effectively storing the hormone and keeping measured levels elevated. Referring to the Letby case, Prof. Chase said: “This ‘impossible’ result is effectively quite common.”
The research was reported by the Daily Telegraph and The Justice Gap. Chase and Shannon had previously argued that significantly higher quantities of insulin than the prosecution alleged would have been required to harm the babies — in the case of Baby L, by a factor of roughly 20 to 80. Sir David Davis MP described the published paper as clear new evidence that should prompt an immediate CCRC referral.
The wider statistical record — May 2026
In May 2026 Prof. Richard Gill — the statistician instrumental in the Lucia de Berk exoneration — published “There to care; not to kill: medical settings, statistics and wrongful convictions” (arXiv), analysing the common structure of wrongful convictions of nurses: no direct evidence of wrongdoing, no CCTV, no confession, and deaths certified at the time as natural. The Letby case features throughout the analysis alongside the de Berk, Poggiali, and earlier UK precedents.
Where the consensus sits today
Taken together, the post-trial scientific record as of mid-2026 reflects convergent concern across multiple independent disciplines. UK and international neonatology, through the Shoo Lee Panel, has concluded that natural-cause explanations are available for each incident. Clinical biochemistry, through the Joint Insulin Report and the 2026 Chase–Shannon paper, has identified significant methodological limitations in the assay evidence and documented that elevated readings occur naturally in preterm babies. Statistical methodology, through the Royal Statistical Society’s 2022–2024 engagement and the peer-reviewed O’Quigley–Gill exchange, has converged on the position that the roster chart should not have been placed before the jury.
This convergence across disciplines is material to the CCRC’s review under the section-13 test. Supporters of a referral argue that the breadth and consistency of post-trial scientific concern, spanning multiple specialties and jurisdictions, is precisely the kind of post-conviction scientific development that the CCRC pathway was designed to address.