Khan & Anor v Harrow Council & Anor

Liability in nuisance for tree-root subsidence requires foreseeability of the particular risk posed by the particular tree. General awareness that trees may cause subsidence, especially on clay soil, is insufficient because it would approach strict liability. The court must consider features such as proximity, size, condition and location. Where a real risk is foreseeable, the landowner must take reasonable steps to eliminate it. Notice is not required to establish liability, although notice and an opportunity to abate may affect recovery of remedial expenditure. A tree preservation order does not prevent necessary works to prevent or abate a nuisance.

The claimants sought damages for subsidence damage to their house, allegedly caused by a Lawson Cypress hedge and an oak tree on the second defendant’s neighbouring property. The claim was brought in nuisance and negligence. The claim against Harrow Council was settled, leaving the claim against the neighbouring owner.

The issues included causation, reasonable foreseeability, the duty to prevent damage, the effect of notice and a tree preservation order, contributory negligence, mitigation and quantum. The court found that the hedge materially contributed to the damage, whereas the oak tree did not give rise to foreseeable liability on the evidence.

1. Liability. The claim succeeded in nuisance in respect of damage caused by the Lawson Cypress hedge H1. The claim failed in respect of damage caused by the oak tree T1.
2. Foreseeability. Applying The Wagon Mound No 2 [1967] 1 AC 617, the relevant question was whether a real risk of damage from the particular trees would have occurred to the mind of a reasonably prudent landowner in the defendant’s position. General knowledge that trees can cause subsidence, particularly on clay, was insufficient. The close proximity, dominating position and condition of H1 made the particular risk foreseeable. No comparable feature made the risk from T1 foreseeable.
3. Preventive duty. Once the risk from H1 was foreseeable, the defendant had to take reasonable steps to eliminate it. Removing the hedge was inexpensive, presented no material difficulty or disadvantage and addressed a risk that was not small. Failure to do so constituted nuisance. Express notice was not a prerequisite to liability.
4. Tree preservation order. Section 198(6)(b) of the Town and Country Planning Act 1990 permitted works necessary for the prevention or abatement of a nuisance. The tree preservation order would not have prevented the necessary reduction of T1 if that tree had otherwise created foreseeable risk.
5. Contributory negligence and damages. The claimants bore 15% responsibility for failing to communicate the risk and damage to the defendant. The recoverable damage attributable to H1 was assessed at 29.3%, including reasonable investigation and remedial costs, loss-adjuster fees and general damages. Judgment was entered for £17,269.84, with interest and costs to be agreed or determined later.

First-instance decision. The claim against Harrow Council had previously been settled. The court determined the remaining claim against the neighbouring landowner.