Roberts & Anor v Bettany & Anor

An intervening act breaks the chain of causation only if its nature and impact reduce the original wrongdoing to part of the surrounding circumstances. The court must consider all the circumstances, particularly the quality, reasonableness, foreseeability and independence of the intervention.

Incompetent or ill-judged remedial work does not automatically constitute a novus actus interveniens. Where urgent intervention responds directly to a hazard created by the defendant, the defendant may bear the risk that the intervener will act without full competence and cause further or different damage.

The claimants alleged that underground fires caused by their neighbours necessitated excavation and infilling works by a local authority. The claimants' property subsequently suffered cracking and subsidence. The defendants relied on expert evidence attributing the excessive settlement to the material and methods used during reinstatement.

The Technology and Construction Court held that the authority's intervention broke the chain of causation and struck out the claim as bound to fail. The claimants appealed. The central issue was whether the remedial works constituted a novus actus interveniens which exculpated the defendants from liability for damage following the original hazard.

1. Appeal allowed unanimously. Buxton LJ, with whom Laws LJ agreed, held that the judge had adopted an unduly mechanistic and narrow approach to novus actus interveniens. The mere incompetence or inadequacy of a third party's intervention does not necessarily break the chain of causation.

2. The issue is one of law. The court must decide whether the third party's conduct is sufficient to exculpate the defendant from liability for the consequences of the defendant's negligent act. That assessment depends on all the circumstances and, particularly, the quality of the later act. Relevant matters include whether the original wrongdoing has become merely historical, whether the intervention was deliberate or wholly unreasonable, whether it was foreseeable, and whether it was wholly independent of the defendant.

3. The necessary impact of an intervening cause was identified consistently with Impress (Worcester) Ltd v Rees (1971) 115 S.J. 245. It must be sufficiently powerful to reduce the defendant's wrongdoing to part of the surrounding circumstances rather than an operative cause.

4. The defendants had created an urgent and unstable underground fire. Excavation was the accepted response, and infilling was necessary to restore support to the claimants' property. The authority's work therefore responded directly to the hazard created by the defendants. Although the expert evidence indicated that the damage could have been avoided, neither the expert nor the judge found that the authority had been negligent.

5. Those circumstances fell far short of establishing a novus actus interveniens. It was at the defendants' peril that a person responding to the hazard might act without full competence and cause further or different injury. The remedial works did not turn the defendants' alleged negligence into a matter of surrounding circumstances.

6. The strike-out was reversed and the action was to proceed to trial. The Court of Appeal declined to give directions about further evidence; those matters were left to the judge managing the trial. Costs were awarded to the appellants in the Court of Appeal and below.

1. Court of Appeal (Civil Division): The appeal was allowed unanimously. The strike-out was reversed, and the action was permitted to proceed to trial.
2. High Court, Queen's Bench Division, Technology and Construction Court: His Honour Judge MacKay treated the local authority's excavation and infilling as a novus actus interveniens and struck out the claim as bound to fail on the available evidence.