R v Cannings — Court of Appeal judgment (December 2003)

Summary of the December 2003 Court of Appeal judgment in R v Cannings. Angela Cannings was acquitted of the murder of her two infant sons. The judgment articulated a specific principle of direct relevance to the Letby case: where a conviction depends on medical expert evidence, and reputable medical experts disagree about the cause of the death or injury, the conviction is unsafe. The post-Panel expert record in the Letby case is a record of reputable medical experts disagreeing with the Crown's causation experts on every indicted case. The Cannings principle therefore applies.

Last updated 2026-04-22

12 min read

Context

The Court of Appeal (Criminal Division) judgment in R v Cannings was handed down on 19 December 2003, quashing the conviction of Angela Cannings for the murder of her two infant sons. The judgment articulated a specific principle of direct relevance to subsequent medical-evidence miscarriage-of-justice cases.

The Cannings principle

The operative formulation: where a conviction depends on medical expert evidence, and reputable medical experts disagree about the cause of the death or injury, the conviction is unsafe. This is not a blanket rule against prosecuting on medical evidence; it is a rule against prosecuting where the medical evidence is itself in genuine dispute among professionals.

Why the principle applies to Letby

The current state of the Letby medical evidence is precisely the state the Cannings principle addresses. Reputable medical experts — fourteen senior international neonatologists on the Shoo Lee Panel, the Joint Insulin Report authors, the independent paediatric pathologists who have reviewed the post-mortem material — disagree with the Crown’s causation experts on every indicted case. On the Cannings principle, the Letby convictions are unsafe.

The post-Meadow sequence

Cannings sits alongside Sally Clark (acquitted 2003) and Donna Anthony (acquitted 2005) as the three major post-Meadow miscarriages of justice. In each case the conviction depended on expert testimony from Sir Roy Meadow or related paediatric-pathology experts. In each case, exoneration followed sustained disagreement from other reputable specialists.

Read alongside

Angela Cannings — biography, The Cannings parallel analysis, Sally Clark — biography, Evidence: Panel consensus.