Trial prosecution v. post-conviction experts
Experts — conflict map
A topic-by-topic map of where named experts agree and disagree, plus the full roster of reviewers on both sides. Each card links to the biographical page where one exists; each carries a claim-status and source-reliability tag. The convictions stand — these are the dispute points feeding the CCRC review.
Where experts disagree
Ten core disputed topics, with the prosecution position on the trial record alongside the post-conviction expert challenge. Click through for the full source-linked evidence card.
| Topic | Prosecution / trial | Post-conviction expert challenge | See |
|---|---|---|---|
| Air embolism | Crown experts (Evans, Bohin) treated skin-mottling patterns as diagnostic of intravenous air embolism, citing Lee & Tanswell (1989). | Lee himself states the descriptions do not match his 1989 criteria. The Panel found no objective evidence of air embolism in the cases reviewed. | Read full → |
| Insulin and C-peptide | Roche immunoassay ratios from the Royal Liverpool laboratory were treated as forensic proof of exogenous insulin. | Independent clinical biochemists (Ismail, Chase, Senn, Allegaert) argue the assay was not forensically validated and no mass-spectrometry confirmation was performed. | Read full → |
| Shift-rota chart and statistical inference | The chart was presented as visually compelling evidence of association between the defendant's presence and a curated set of events. | The RSS, Gill, Fenton, Hutton, Spiegelhalter, Green, Schneps and O'Quigley each identify selection bias, base-rate neglect and Texas-sharpshooter logic. Standards established after Sally Clark were not met. | Read full → |
| Handwritten notes (Post-its) | Notes including 'I am evil I did this' were treated by the Crown as confessional material. | Defence and post-conviction commentators argue the notes match self-blame psychology in clinicians under sustained accusation, a documented pattern in the patient-safety literature. | Read full → |
| Child K — alleged eyewitness count | Dr Ravi Jayaram gave 2024 retrial evidence of observing the defendant standing over Child K without acting during desaturation; conviction on one count of attempted murder. | Independent clinicians (Hummler and others) have published technical analysis of the ET-tube and ventilation mechanism, arguing the timing and physiology are consistent with displacement and re-intubation. | Read full → |
| NEC vs air-injection on radiology | 'Air' findings on imaging were attributed to deliberate injection. | Independent paediatric radiologists have re-read the imaging and argue findings are consistent with NEC (pneumatosis intestinalis, portal venous gas). | Read full → |
| Late-onset sepsis differential | Sepsis was not advanced by the Crown as a primary explanation for the collapses on the indicted counts. | Post-conviction expert review argues sepsis was not adequately excluded as a primary cause before attribution to deliberate harm. | Read full → |
| Liver-injury and post-mortem findings | Liver findings in some cases were attributed to deliberate trauma. | Independent expert re-analysis filed with the CCRC and the resuscitation-trauma literature argue for natural and resuscitation-related explanations. | Read full → |
| RCPCH 2016 invited review | Used at trial as a backdrop to the prosecution timeline. | Post-trial analysis questions the scope and limits of the RCPCH review and how its findings were interpreted by Trust and investigators. The review did not identify a perpetrator. | Read full → |
| Door-swipe data mislabelling | Door-swipe records were used at trial to place Letby on the unit at relevant times. The Crown treated the records as objective placement evidence. | The CPS confirmed in August 2024 that swipe data for one of the unit's doors had been mislabelled — entries and exits reversed. The bad data was relied on in evidence relating to nine infants and played a central role in the Child K count. A second door did not record entries or exits at all. | Read full → |
| Crown insulin expert's GMC investigation — non-disclosure to jury | Prof. Peter Hindmarsh gave expert evidence for the Crown on the insulin counts (Babies F and L) at the 2022–2023 trial. | The GMC opened a fitness-to-practise investigation into Hindmarsh the same day he began giving evidence; a medical tribunal concluded the allegations 'may have the potential to impact on his ability to act as an expert witness'. The jury was never told. Hindmarsh voluntarily erased himself from the GMC register on 14 November 2024, ending the investigation without a regulatory finding. | Read full → |
| Expert-evidence methodology and disclosure | Dr Dewi Evans was the principal medical reviewer of all counts; Dr Sandie Bohin served as corroborating expert. | Independent expert critique (Heneghan, Goldacre) and legal commentary (Mansfield, Kennedy, Sumption) argue the methodology fails EBM standards and may engage the Cannings principle. | Read full → |
Trial prosecution experts
5 expertsDr Dewi Evans
Lead causation expert at trial
Main contribution: Provided the principal medical-causation narrative across the indictment, diagnosing air embolism, exogenous insulin and gastric-air administration as mechanisms of harm.
Key claim: Skin-discolouration patterns and gas findings were diagnostic of deliberate harm via intravenous air, insulin administration and air-in-stomach.
Criticism: Methodology rejected by the 14-member Shoo Lee International Expert Panel (Feb 2025). Lee himself states the prosecution misapplied his 1989 paper. A family court judge separately described an unrelated Evans expert report as 'worthless' (2023). Self-referred to Cheshire Police; out of routine NICU practice for over a decade at the time of trial.
Related evidence
Dr Sandie Bohin
Second-opinion neonatology expert at trial
Main contribution: Largely corroborated Dr Evans's conclusions at trial.
Key claim: Supported the air-embolism and insulin theories advanced by Dr Evans.
Criticism: Independent neonatologists argue her conclusions rest on the same methodology as Dr Evans's and inherit its limitations — same-methodology-second-clinician rather than independent corroboration.
Related evidence
Dr Andreas Marnerides
Reviewing pathologist for the prosecution
Main contribution: Re-read original autopsy material on behalf of the Crown.
Key claim: Identified pathology findings the Crown argued were consistent with the deliberate-harm mechanisms.
Criticism: Independent expert re-analysis filed with the CCRC argues the preserved post-mortem material is compatible with natural pathology.
Related evidence
Prof. Owen Arthurs
Paediatric radiology expert for the prosecution
Main contribution: Gave post-mortem radiology evidence for the Crown.
Key claim: Radiological findings were consistent with the prosecution's mechanisms (intravascular gas, air-in-stomach).
Criticism: Independent paediatric radiologists have re-read the imaging and argue the findings are more consistent with NEC, sepsis and other natural causes than with the prosecution's deliberate-harm framing.
Related evidence
Prof. Peter Hindmarsh
Crown's insulin expert
Main contribution: Endocrinology evidence on the two insulin counts (Babies F and L) at the 2022–2023 trial.
Key claim: Low insulin-to-C-peptide ratios were diagnostic of exogenous insulin administration.
Criticism: The GMC opened a fitness-to-practise investigation into Hindmarsh on the same day he began giving evidence at the Letby trial in late 2022; the medical tribunal concluded the allegations 'may have the potential to impact on his ability to act as an expert witness' but the jury was never told. Hindmarsh removed himself from the GMC register through voluntary erasure on 14 November 2024, ending the investigation without a regulatory finding. Independent clinical biochemists (Ismail, Chase, Senn) have separately argued the Roche immunoassay used at trial was not forensically validated and that confirmatory mass spectrometry was not performed.
Related evidence
Trial defence experts
1 expertDr Michael Hall
Defence neonatology expert at trial
Main contribution: Instructed neonatology expert for the defence at the original trial. His post-trial public commentary is a rare direct insider account of what the defence saw and how the medical evidence was received.
Key claim: Mechanisms advanced by the Crown were not the only available explanations for the observed collapses; natural-cause differentials were available.
Related evidence
Post-conviction medical experts
18 expertsDr Shoo K. Lee
Chair, International Expert Panel (Feb 2025)
Main contribution: Convenor of the 14-member International Expert Panel that reviewed the medical evidence for every indicted count. Lead author of the 1989 air-embolism paper cited by the prosecution.
Key claim: The skin signs described at trial do not match the findings in his own 1989 paper. The Panel found no medical evidence of deliberate harm in any case reviewed.
Related evidence
Prof. Neena Modi
Panel member — UK neonatal medicine
Main contribution: Past President RCPCH; UK Panel member. Senior UK neonatologist publicly calling for an urgent review of the convictions.
Key claim: The medical evidence underpinning the convictions warrants urgent independent review.
Related evidence
Prof. Mikael Norman
Panel member — Karolinska
Main contribution: Swedish Panel member; leads the Swedish Neonatal Quality Register.
Key claim: Findings consistent with natural causes in unstable preterm infants on a Level-2 unit; no objective evidence of deliberate harm in the cases reviewed.
Related evidence
Prof. Prakesh Shah
Panel member — Canadian Neonatal Network
Main contribution: Director, Canadian Neonatal Network. Population-outcomes calibration to the case-by-case review.
Key claim: Findings consistent with the natural-cause differential expected on a Level-2 unit handling sub-designation gestation babies.
Related evidence
Prof. Helmut Hummler
Panel member — Ulm; neonatal ventilation
Main contribution: German Panel member. Research focus on neonatal ventilation and lung physiology.
Key claim: Several indicted cases turn on ventilation and ET-tube events whose physiology is consistent with the natural-cause differential.
Related evidence
Dr Adel Ismail
Independent clinical biochemist
Main contribution: Published authority on insulin-immunoassay interference. Established that the Roche assay used in the case is not a forensic test.
Key claim: The Roche insulin immunoassay can produce the trial result via auto-antibodies, sepsis, adrenal suppression and other non-exogenous-insulin causes; confirmatory mass spectrometry was not performed.
Related evidence
Prof. Geoff Chase
Independent physiological-modelling expert
Main contribution: Demonstrates that the reported insulin values are not plausible on the Crown's theory; the numbers belong to adult attempted-suicide presentations, not to an infant spiked via a TPN bag.
Key claim: On the Crown's own theory of administration, the recorded insulin values are not physiologically reachable.
Related evidence
Dr Sarrita Adams
Biomedical scientist (science4justice.nl)
Main contribution: 'The insulin question' (Oct 2023) remains the canonical plain-English summary of why the Letby insulin evidence fails a forensic standard.
Key claim: Roche Cobas manufacturer guidance, the 2010/2012 Liverpool lab protocol change, false-positive literature, and sample-handling failures undermine the forensic use of the assay.
Related evidence
Dr Michael Fox
Diving-medicine specialist (RN Submarine Escape Tank)
Main contribution: Retired Royal Navy diving-medicine consultant. Air-embolism mechanism specialist with operational hyperbaric experience.
Key claim: The volumes, vascular access points and time-course alleged at trial are not consistent with the operational physiology of intravenous air embolism in a preterm infant.
Related evidence
Dr Martyn Pitman
Retired consultant obstetrician
Main contribution: Case-by-case clinical analysis of Children A/B, C, D, O and P, with attention to obstetric history.
Key claim: Per-case clinical record supports natural-cause readings for the cases analysed.
Dr Peter Donnelly
Microbiologist; hospital infection-control specialist
Main contribution: Pseudomonas/sewage and infection-control angle on the unit's documented environmental issues.
Key claim: Documented infection-control failures on the unit during the indictment period are part of the natural-cause differential.
Related evidence
Dr Waney Squier
UK paediatric neuropathologist
Main contribution: Shaken Baby Syndrome miscarriage-of-justice profile. Independent paediatric-neuropathology perspective on disputed post-mortem inferences.
Key claim: Forensic over-attribution of trauma findings to single mechanisms is a recurring problem in paediatric pathology and applies to the Letby record.
Related evidence
Dr Svilena Dimitrova
NHS consultant neonatologist; GMC complainant
Main contribution: Co-filed (with Roger Norwich) a formal GMC complaint regarding the prosecution expert evidence of Dr Dewi Evans, on the basis that the trial expert evidence did not meet professional standards.
Key claim: The theories proposed in court were not plausible and the prosecution was full of medical inaccuracies. While she cannot assert Letby's innocence, she sees 'no proof of guilt'.
Related evidence
Helen Shannon
Insulin physiological-modelling collaborator
Main contribution: Collaborator with Prof. Geoff Chase on the physiological-modelling analysis of the insulin values reported in the Letby case.
Key claim: On the Crown's theory of administration, the reported insulin values would have required quantities of insulin far in excess of what the alleged mechanism could deliver.
Related evidence
Prof. Gísli Guðjónsson CBE
World-leading expert on confession evidence
Main contribution: Emeritus Professor of Forensic Psychology, King's College London. Author of the canonical scholarly work on false confessions; gave evidence in the appeals of the Guildford Four, Birmingham Six, Stefan Kiszko, Judith Ward, Derek Bentley and Sally Clark. Creator of the Gudjonsson Suggestibility Scale.
Key claim: Interviewed Lucy Letby twice in summer 2025 and produced a report addressing the psychology of the handwritten notes found at her home, applying the established literature on self-blame writing by individuals under sustained institutional accusation.
Related evidence
Dr Faye Skelton
Forensic psychology — applied criminology
Main contribution: Programme lead of Applied Criminology and Forensic Psychology at Edinburgh Napier University. Featured in the Channel 5 documentaries 'Lucy Letby: Did She Really Do It?' (October 2024) and 'Lucy Letby: The New Evidence' on the psychology of the handwritten notes and clinician-under-investigation framing.
Key claim: The handwritten notes reflect extreme mental distress in an experienced and trusted nurse under sustained accusation; not forensic confession.
Related evidence
Prof. Carl Heneghan
Director, Oxford Centre for Evidence-Based Medicine
Main contribution: Flagship UK EBM voice. Sustained public commentary applying the EBM framework to the Letby evidence.
Key claim: The Crown's medical methodology does not meet EBM standards.
Related evidence
Prof. Ben Goldacre
Professor of Evidence-Based Medicine, Oxford
Main contribution: Author of Bad Science and Bad Pharma. Framework for identifying unreliable medical claims applied to the Letby evidence.
Key claim: The Crown's medical case displays features the Bad Science framework would flag as unreliable.
Related evidence
Post-conviction statistical experts
8 expertsProf. Richard Gill
Mathematical statistics; Lucia de Berk lead
Main contribution: Led the statistical critique that overturned Lucia de Berk's conviction. Public author of the statistical critique of the Letby shift-rota chart since 2023.
Key claim: The shift-rota chart is a textbook example of selection bias (the Texas sharpshooter fallacy).
Related evidence
Prof. Norman Fenton
Bayesian networks in legal evidence
Main contribution: Sustained Bayesian-network analysis of the Letby evidence. The most detailed publicly available Bayesian critique.
Key claim: Posterior probability of guilt on the trial evidence does not meet the criminal-law threshold.
Related evidence
Prof. Jane Hutton
Medical statistics (Warwick)
Main contribution: Operational analysis of the Letby shift-rota chart identifying four specific methodological failures.
Key claim: The chart conflates rate and count, uses the wrong denominator, has no null-hypothesis comparison, and pattern-matches against pre-selected events.
Related evidence
Sir David Spiegelhalter
Statistics (Cambridge); past-president RSS
Main contribution: UK's most widely recognised statistical-communicator voice. Framework for statistical evidence in criminal trials applied directly to the Letby chart.
Key claim: Statistical-evidence standards established after Sally Clark apply to the Letby chart and were not met.
Related evidence
Prof. Peter Green
Statistics (Bristol); past-president RSS
Main contribution: UK-specific statistical commentary on the shift-rota chart referencing RSS post-Sally-Clark guidance.
Key claim: The presentation of the chart to the jury did not meet the RSS post-Clark framework.
Related evidence
Prof. Leila Schneps
Mathematician; 'Math on Trial' author
Main contribution: 'Math on Trial' (2013) is the canonical popular reference on mathematical fallacies in criminal trials. Four catalogued fallacies apply directly to the Letby chart.
Key claim: The chart exemplifies multiple recognised mathematical fallacies in criminal-trial evidence.
Related evidence
Prof. John O'Quigley
Emeritus Professor of Statistics, UCL
Main contribution: Published proportional-hazards correction to the shift-chart reading.
Key claim: Proper proportional-hazards treatment of the shift data does not support the inference offered to the jury.
Related evidence
Prof. Stephen Senn
Statistician and methodologist (Edinburgh)
Main contribution: Statistical-evidence critique with direct relevance to healthcare-serial-killer prosecutions.
Key claim: The methodological standards required for statistical evidence in serial-attribution cases were not met.
Related evidence
Post-conviction legal commentators
7 expertsLord Sumption
Former Supreme Court Justice
Main contribution: Former Supreme Court Justice (2012–2018). One of the most senior retired English judges to call publicly for the safety of the convictions to be reviewed.
Key claim: On the public evidence, there is a serious case that the convictions are unsafe and warrant CCRC referral.
Michael Mansfield KC
Civil-liberties barrister
Main contribution: Career miscarriage-of-justice silk (Birmingham Six, Guildford Four, Hillsborough). Public commentary since 2023 identifying the Letby case as a miscarriage in the making.
Key claim: The Letby case displays the structural features of previous English miscarriages of justice.
Baroness Helena Kennedy KC
Doughty Street barrister; Labour peer
Main contribution: Senior UK barrister; career focus on miscarriages of justice and systemic prejudice against women defendants.
Key claim: The procedural and evidential framework of the Letby case warrants the CCRC review.
Geoffrey Robertson KC
Founder of Doughty Street Chambers
Main contribution: Human-rights barrister; commentary on expert-evidence standards and CCRC referral mechanics.
Key claim: Expert-evidence standards required for serial-attribution prosecutions were not met.
Prof. Clive Walker
Emeritus Professor of Criminal Justice Studies, Leeds
Main contribution: Co-editor of the canonical UK academic reference works on miscarriages of justice.
Key claim: The October 2025 supplementary CCRC submissions operationalise the established miscarriage-of-justice framework.
Roger Norwich
Medico-legal expert; GMC complainant
Main contribution: Co-filed (with Dr Svilena Dimitrova) a formal GMC complaint regarding the prosecution expert evidence in the Letby trial.
Key claim: Both Crown expert witnesses failed to provide balanced, impartial views, instead giving the court opinions that would not be supported by most doctors.
Related evidence
Clive Stafford Smith
Human-rights lawyer; founder of Reprieve
Main contribution: Long-running miscarriage-of-justice campaigner. Public engagement with the Letby case post-Panel.
Key claim: The Letby record warrants the same disciplined re-examination as previous miscarriage-of-justice cases.
Inquiry witnesses
3 expertsDr Nim Subhedar
External neonatology reviewer; Liverpool Women's Hospital
Main contribution: Consultant neonatologist; Thirlwall Inquiry external reviewer.
Key claim: Inquiry evidence on the unit's clinical capability during the indictment period.
Dr Jane Hawdon
External neonatology reviewer; Thirlwall witness
Main contribution: Consultant neonatologist; Thirlwall external reviewer.
Key claim: Inquiry evidence on the unit's neonatal practice during the indictment period.
Alexandra Mancini
External senior-nurse reviewer; Thirlwall witness
Main contribution: Senior neonatal nurse; Thirlwall external reviewer.
Key claim: Inquiry evidence on nursing standards and handover practice on the unit.
Professional bodies
2 expertsRoyal Statistical Society
UK statistics professional body
Main contribution: Post-Sally-Clark framework on statistical evidence in criminal trials. Sustained engagement with the shift-rota chart.
Key claim: Statistical evidence in cases of this structure should meet the RSS post-Clark framework. The chart presentation did not.
Related evidence
Royal College of Paediatrics and Child Health
UK paediatrics professional body
Main contribution: Conducted the 2016 invited review of the Countess of Chester neonatal unit; ongoing engagement with the case via guidance evolution.
Key claim: Clinical-care concerns identified by the 2016 review; the review did not identify a perpetrator.
Related evidence
Full Shoo Lee Panel roster
Convened by Dr Shoo K. Lee — Professor Emeritus of Paediatrics, University of Toronto; former Paediatrician-in-Chief, Mount Sinai Hospital Toronto.
Dr Shoo K. Lee
Chair; Professor Emeritus, University of Toronto
Canada
Dr Eric Eichenwald
Professor of Pediatrics, University of Pennsylvania; Chief of Neonatology, Children's Hospital of Philadelphia
United States
Dr Helmut Hummler
Senior Medical Director, European Foundation for Care of Newborn Infants
Germany
Dr Tetsuya Isayama
Head, Division of Neonatology, National Center for Child Health and Development, Tokyo
Japan
Dr Joanne Langley
Head, Division of Pediatric Infectious Diseases, Dalhousie University
Canada
Professor Neena Modi
Professor of Neonatal Medicine, Imperial College London
United Kingdom
Sandra Moore RN
Staff Nurse, NICU, Southlake Regional Health Centre
Canada
Professor Mikael Norman
Professor of Paediatrics and Neonatal Medicine, Karolinska Institutet
Sweden
Professor Bruno Piedboeuf
Professeur titulaire en pédiatrie, Université Laval
Canada
Professor Prakeshkumar Shah
Professor of Pediatrics, University of Toronto
Canada
Professor Nalini Singhal
Professor Emeritus, University of Calgary
Canada
Professor Erik Skarsgard
Professor, Division of Pediatric Surgery, University of British Columbia
Canada
Dr Ann R. Stark
Professor in Residence of Pediatrics, Harvard Medical School
United States
One member (anonymous)
Has chosen to remain anonymous for the time being (per the Panel report)
Not disclosed
Reported by:
- BBC News — 3 February 2025
- The Guardian — 3 February 2025
- The Telegraph — 3 February 2025
- Private Eye — Issue 1619
What this map is and is not
The conflict map records where experts have publicly disagreed. It is not a quorum count; a higher number of experts on one side does not by itself decide the question. Each expert’s claim is labelled by claim-type and source level so the reader can judge the weight to give it. The convictions currently stand; the CCRC review is not a finding of innocence or guilt.
For the methodology behind the source-reliability scale see source-reliability methodology. For the editorial limits see what this site is not saying. For a comparator on the wider problem of expert-witness reliability in English criminal trials, see the Tom Hayes biography (LIBOR exoneree; UK Supreme Court 2025).