Primacy of Expert Medical Timing Evidence in Child Care Fact-Finding: O (Children: Fact-Finding) [2025] EWCA Civ 479

1. Introduction

This commentary examines the Court of Appeal’s April 2025 decision in O (Children: Fact-Finding), [2025] EWCA Civ 479, which clarifies the weight to be accorded to expert medical evidence on injury timing in care proceedings. The case arose from care proceedings brought by the local authority after C, a three-week-old infant from a travelling family, suffered severe head injuries including a diffuse axonal injury (DAI) and skull fracture. The primary question was whether the most serious injuries occurred during an admitted assault on the infant’s mother on 25 November 2023, or in a second undisclosed event on the day of the baby’s hospital readmission. His Honour Judge North at first instance found all injuries dated to the single assault; the local authority appealed, relying on unopposed expert opinion that the DAI could only have occurred between the two hospital visits.

2. Summary of the Judgment

The Court of Appeal (Jackson LJ, Males LJ, King LJ) allowed the appeal. Lord Justice Jackson held that the first-instance judge’s conclusion—that the local authority had not proved a second event—was not reasonably open to him. On the unchallenged medical evidence, the DAI and skull fracture had to post-date the first hospital attendance. The baby’s normal observations on that visit, the experts’ consensus that DAI is not a “slow burn” injury and the absence of any clinical finding at first attendance meant that the only realistic window for the serious injury was the interval between the two admissions. Lay evidence from the parents, tainted by five months of deceit, could not displace that objective expert consensus. Jackson LJ substituted findings that (1) the parents had concealed the facts of the initial assault, and (2) there was a second undisclosed event between admissions in which the DAI was inflicted.

3. Analysis

3.1 Precedents Cited

• Re B (Care: Expert Witnesses) [1996] 1 FLR 667 – the enduring principle that “the expert advises, the judge decides,” emphasizing the court’s ultimate function in weighing expert evidence against other evidence.
• R v Cannings [2004] EWCA Crim 1 and Re U (A Child) [2004] EWCA Civ 567 – authority for caution in accepting expert medical certainty, though here the experts worked within well-understood boundaries rather than at the frontiers of science.
• Henderson v Foxworth Investments Ltd [2014] UKSC 41 – appellate restraint in overturning a trial judge’s factual findings unless no reasonable judge could have arrived at them.

3.2 Legal Reasoning

The Court of Appeal’s reasoning unfolds in three stages:

1. Strength of Expert Evidence: The experts uniformly agreed that DAI and the skull fracture could not have pre-dated the first hospital visit, which recorded normal vital signs and no neurological compromise. None of the experts suggested a lacuna in medical knowledge; rather, they treated the trajectory of such injuries as well understood.
2. Insufficiency of Lay Evidence: The only non-medical evidence came from parents whose credibility was undermined by repeated lies over five months. The first-instance judge had not made positive findings of their veracity about the critical period, yet he treated their account as sufficient to displace the expert consensus.
3. Appellate Intervention: Applying the high standard of review from Henderson, the Court of Appeal held that no reasonable judge, faced with the solid expert timing evidence, could have found only one assault. The judge’s attempt to invoke a hypothetical future medical discovery was unsupported by the evidence and revealed an impermissible search for alternative explanations.

3.3 Impact of the Decision

This decision establishes that in care proceedings, where expert medical witnesses of the highest calibre agree on the timing and mechanism of serious injury, a fact-finding court may not lightly reject or dilute that consensus on the basis of equivocal lay testimony. It reinforces the primacy of objective medical evidence in determining causation timelines and signals that appellate courts will readily intervene where a trial judge’s balancing of evidence produces an outcome at odds with unchallenged expert consensus. Future care and safeguarding cases involving head injuries and DAI will be guided by this principle, ensuring greater consistency and scientific rigour in fact-finding hearings.

4. Complex Concepts Simplified

• Diffuse Axonal Injury (DAI): A form of brain injury caused by shearing forces that damage nerve fibres. It typically produces immediate and observable changes in consciousness and behaviour; it is not a condition that “evolves slowly.”
• Lucas Direction: A jury-style direction reminding the fact-finder that an accused’s lie may be understandable in context and that guilt must be proved beyond reasonable doubt (or, in civil/care proceedings, on the balance of probabilities) notwithstanding false statements.
• Appellate Restraint (Henderson Test): An appellate court may only overturn a trial judge’s findings of fact if satisfied that no reasonable trial judge could have reached the impugned conclusion.

5. Conclusion

The Court of Appeal’s judgment in O (Children: Fact-Finding) crystallizes a new, binding principle in child care fact-finding: where expert medical witnesses are agreed on the timing of serious injuries, that consensus cannot be displaced by equivocal or self-serving lay evidence. The decision underscores the court’s role in robustly testing lay testimony against sound scientific evidence and reaffirms appellate willingness to correct fact-finding errors when a trier of fact departs unreasonably from uncontradicted expert opinion. This case will serve as authoritative guidance for practitioners and judges in future care proceedings involving complex medical causation issues.