A Local Authority v AA & Ors.

In fact-finding proceedings concerning suspected abusive head trauma, the local authority bears the burden of proving causation on the balance of probabilities. The court must assess the totality of the evidence, including medical evidence, the carers’ evidence, the surrounding circumstances and any reasonably possible unknown or unusual cause. Medical opinion is important but does not determine the issue. The judge must remain alert to developments in scientific knowledge and may depart from expert opinion for sound reasons. A diagnosis based on subdural and retinal haemorrhages does not automatically establish abusive injury, although those findings may commonly support that conclusion. The court must consider whether an accidental mechanism remains a genuine possibility, including in an unusual or outlier case.

The local authority sought findings that the father had caused a nine-month-old child’s subdural and retinal haemorrhages by shaking her. The father said that she had fallen from a bed, and the mother supported his account. The court heard evidence from several medical experts and considered extensive academic literature concerning abusive head trauma, short falls, benign enlargement of the subarachnoid spaces and head circumference.

The principal issue was whether the injuries were caused by shaking or by the reported fall, applying the balance of probabilities and considering the evidence as a whole.

1. Burden and standard. The local authority bore the burden of proving its case on the balance of probabilities. The court had to decide causation from all the evidence and not from suspicion, speculation or medical evidence considered in isolation.
2. Role of expert evidence. Medical opinions carried considerable weight, but the roles of the experts and the court remained distinct. The judge had to evaluate expert evidence alongside the evidence of the parents, the circumstances of the alleged event and the child’s presentation. The court could reach a conclusion different from that of the experts where sound reasons existed.
3. Unknown and unusual causes. The court had to factor into its assessment the possibility that the cause remained unknown or that the case was an unusual outlier. This did not alter the burden or standard of proof. The medical literature did not establish that subdural and retinal haemorrhages could never result from a short fall.
4. Assessment of this case. The absence of bruising or fractures, the absence of relevant risk factors, the normal and contented circumstances before the incident, the father’s credibility and the 999 call supported his account. The evidence of a possible short-fall mechanism, the relatively slight injuries and the child’s unusually large head also remained relevant. Although shaking was considered more likely by the experts, a short fall remained a genuine possibility.
5. Disposition. Considering the totality of the evidence, the court was not satisfied that the father had shaken the child or caused the injuries. The local authority’s Threshold Document was not proved.