Loftus-Brigham & Anor v London Borough of Ealing

Where damage may have been caused concurrently by neighbouring trees and other vegetation, the claimant need not prove that the defendant’s trees were the sole, main or dominant cause. It is enough to prove on the balance of probabilities that moisture extraction by those trees was an effective cause which materially contributed to the damage.

A court must not compare the relative causal potency of concurrent causes by requiring the defendant’s trees to be dominant. The causation principles are the same whether the claim is framed in nuisance or negligence, and no special causal rule applies merely because the alleged cause is tree roots.

The claimants owned a house built on highly plastic London clay. They alleged that roots from trees maintained by the local authority had desiccated the sub-soil and caused subsidence. The authority contended that climbers growing over the house, including Virginia creeper and wisteria, were responsible or had contributed.

His Honour Judge Hallgarten QC dismissed the claim in the Central London County Court on 19 May 2003. He held that the claimants had not proved that the authority’s trees were probably the dominant cause. He would have rejected the pleaded defence of contributory negligence.

The claimants appealed. The central issue was whether causation required proof that the trees were the dominant cause, or proof that they were an effective and substantial cause of the damage.

The Court of Appeal allowed the appeal. The court’s joint judgment held that the judge had applied an erroneous test of causation. His order was set aside and the action was remitted to the Central London County Court for a retrial before a different judge.

1. The distinction between nuisance and negligence did not affect the causal inquiry in this context. Consistently with Delaware Mansions and the causal analysis approved in Fairchild, the common law required the fair and just content of the neighbouring owner’s duty to be identified; the label attached to the claim did not alter the applicable causation principles.

2. In a case of concurrent causes, the claimant need not establish that the defendant’s act was the only or main cause. Banque Bruxelles established that an effective cause suffices. Bonnington Castings, as approved in Fairchild, required proof on the balance of probabilities that the relevant breach caused or materially contributed to the injury. A substantial contribution could be established where the contribution was not negligible. The same general principles applied to alleged tree-root subsidence; there was no separate rule for such cases.

3. The judge’s requirement that the authority’s trees be the dominant cause was impermissible. “Dominant” has a comparative meaning which “substantial” does not. The judge had compared the trees with the climbers and had treated the presence of another causally potent source as defeating the claim. He should instead have asked whether desiccation caused by the tree roots materially contributed to the damage.

4. The existing findings did not permit the Court of Appeal confidently to resolve that question itself. A retrial before a different judge was appropriate because the original reasoning, and much of the expert evidence, had proceeded on the mistaken dominant-cause issue.

5. The court also rejected the suggested apportionment of loss based merely on causation. Apportionment depended on legal liability. Since the unappealed finding was that the claimants were not contributorily negligent, they bore no legal liability for damage caused by their vegetation. The authority had to take its victim as it found it.

• Court of Appeal (Civil Division) — Allowed the appeal, set aside the order, and remitted the action for retrial before a different judge: [2003] EWCA Civ 1490.
• Central London County Court — On 19 May 2003, His Honour Judge Hallgarten QC dismissed the claim after holding that the claimants had not shown that the authority’s trees were probably the dominant cause of the damage.