Lucia de Berk (Netherlands)
Dutch paediatric nurse. Convicted 2003 of multiple murders on statistical and medical-reinterpretation evidence. Acquitted by the Dutch Supreme Court in April 2010 after Prof. Richard Gill and others demonstrated the evidence was structurally unsound. Key exonerating features: selection-effect critique of the statistical calculation; unblinded retrospective medical reinterpretation; hospital management with institutional incentive to prefer individual explanation.
The closest direct international parallel to Letby. See our Lucia de Berk parallel analysis.
Susan Nelles (Canada)
Canadian registered nurse. Charged in 1981 with four murders at the Hospital for Sick Children in Toronto after a cluster of cardiac-arrest deaths attributed to digoxin overdose. Released at preliminary hearing in 1982 for lack of evidence. No criminal conviction; never tried. The Grange Royal Commission investigation (1983–1984) and subsequent reviews did not identify a deliberate perpetrator. The Hospital for Sick Children cluster remains formally unexplained.
Relevance: the Canadian system correctly declined to prosecute a suspected medical-cluster case where the evidence did not meet the criminal threshold. Nelles was later compensated for the initial prosecution. The case established institutional lessons in Canadian policing on suspect-first versus cluster-first scoping — lessons directly relevant to the Letby Hummingbird scoping question.
Daniela Poggiali (Italy)
Italian nurse. Convicted 2016 of murdering two patients. Acquitted at first appeal 2017; conviction reinstated; retried; acquitted by the Italian Supreme Court in 2021. Central issues: statistical evidence on shift-overlap with deaths, similar in structure to the Letby shift-rota chart; retrospective medical reinterpretation; expert disagreement. Italian judicial review eventually concluded the evidence did not reach the criminal threshold.
Relevance: another European case resolved through judicial review in favour of the defendant on structurally similar statistical and medical-interpretation evidence. The Italian Supreme Court, like the Dutch Supreme Court in the de Berk case and the UK Court of Appeal in the Cannings case, declined to sustain a conviction on disputed medical-expert evidence.
Colin Norris (UK)
UK nurse. Convicted 2008 of murdering four elderly patients with insulin at Leeds General Infirmary. The case turned on insulin-blood-sugar readings the Crown interpreted as deliberate hypoglycaemic induction. The CCRC referred Norris’s case to the Court of Appeal in 2021 on the basis of new expert evidence that spontaneous hypoglycaemia in the relevant patient population was more common than had been believed at trial. Status of the appeal remains ongoing as of 2026.
Relevance: a direct UK precedent for CCRC referral of a UK nurse-and-insulin case on the basis of subsequent expert-evidence shift. The Norris application is the most directly analogous CCRC reference to the Letby application. Both feature: insulin-related medical evidence, CCRC engagement, subsequent expert-evidence shifts, and the real-possibility test.
The template across cases
Common features across the comparator cases:
- A hospital identifies a cluster of unexpected deaths associated with a specific staff member’s shifts.
- Statistical evidence is developed on the shift-overlap pattern.
- Medical evidence is retrospectively reinterpreted to fit the suspect hypothesis.
- Expert disagreement emerges over the retrospective reinterpretation.
- The conviction is ultimately reviewed on the expert-disagreement ground.
The Letby case fits the template in every element. The comparator cases suggest the template-review typically produces acquittal, non-prosecution, or retrial. It does not typically sustain the original conviction.
What the international pattern tells us
The UK Letby conviction is, in the context of international comparator cases, the outlier that has not yet been reviewed on the expert-disagreement ground. The comparator cases are all cases in which that review did happen — sometimes after years, sometimes after decades — and resulted in the conviction being disturbed.
The October 2025 Letby CCRC application is asking the UK criminal-justice system to apply the same review the comparator systems have applied. The pattern of outcomes across comparators suggests the review, when genuinely applied, produces a different answer from the original verdict.