Colin Campbell v R

On an appeal based on fresh expert evidence, the appellate court must decide whether the convictions are safe, rather than speculate about what a jury might have made of the new material. Under section 23 of the Criminal Appeal Act 1968, the statutory considerations require specific attention but are not exhaustive or conclusive.

A proposed natural explanation for severe hypoglycaemia must be assessed against the individual clinical evidence. Considering whether that explanation is rare is legitimate; it does not amount to using statistics as a diagnostic shortcut. An unverified theoretical hypothesis which does not explain the sudden, profound and treatment-refractory pattern established in the cases will not render convictions unsafe.

Colin Campbell v R concerned convictions for four murders and one attempted murder arising from severe hypoglycaemia suffered by five elderly hospital patients under the appellant’s care. The appellant was convicted at the Crown Court at Newcastle upon Tyne in 2008. His first appeal against conviction was dismissed in [2009] EWCA Crim 2697.

The Criminal Cases Review Commission referred the convictions on the basis of fresh expert evidence. The appellant contended that frailty, age and co-morbidities could provide natural explanations for the hypoglycaemia in four cases and, consequently, undermine the remaining murder conviction. The prosecution relied on rebuttal expert evidence that the observed clinical pattern was characteristic of exogenous insulin administration.

The central issue was whether the fresh medical evidence rendered any conviction unsafe.

1. Appeals dismissed. The court had no doubt that all five convictions were safe.
2. The court received the fresh evidence under section 23 of the Criminal Appeal Act 1968. The statutory considerations required specific attention but were neither exhaustive nor conclusive. The appellant’s experts were credible and their evidence was admissible. It was just and expedient to test their hypothesis, together with the prosecution’s rebuttal evidence, before the court.
3. The court’s task was to decide safety, not guilt. It was therefore not required to ask what a jury might have made of the fresh hypothesis. It had to assess the hypothesis against the evidence as a whole and determine whether it undermined the convictions.
4. It was legitimate to consider the rarity of the proposed natural explanation. The court rejected the submission that this involved the forbidden statistical fallacy. Rarity was relevant to whether the explanation was medically credible; it was not used as a diagnostic tool to prove guilt.
5. The fresh hypothesis did not explain the defining clinical features of the four disputed cases: sudden, severe and profound hypoglycaemia, requiring large and repeated doses of glucose and showing a refractory or oscillating response to treatment. The additional patients relied upon by the appellant had identifiable natural pathology and their hypoglycaemia was materially easier to correct. They therefore reinforced rather than undermined the distinction drawn by the prosecution experts.
6. The hypothesis had not been established by relevant clinical experience, peer-reviewed literature or a satisfactory physiological account of the refractory episodes. A merely theoretical possibility did not assist the appeal. The prosecution’s rebuttal did not advance a new case, but tested the fresh evidence against the unchanged trial case.
7. The conviction concerning Mrs Hall was independently safe on substantial circumstantial evidence. The jury had also been entitled, while considering each count separately, to treat the proved administration of exogenous insulin to her as relevant evidence on causation and identity in the other cases.

• Court of Appeal (Criminal Division): On a Criminal Cases Review Commission reference, dismissed the renewed appeal against conviction: [2025] EWCA Crim 795.
• Court of Appeal (Criminal Division): Dismissed the appellant’s first appeal against conviction: [2009] EWCA Crim 2697.
• Crown Court at Newcastle upon Tyne: In 2008, convicted the appellant of four murders and one attempted murder and imposed life sentences for murder and a concurrent sentence of imprisonment for public protection for attempted murder.