Marc Christopher Davies v Bridgend County Borough Council

In a nuisance claim involving Japanese knotweed, a claimant may recover diminution in value where the loss is consequential on an actionable physical interference with the claimant’s land. Such loss is not pure economic loss merely because it is measured by a reduction in market value. The restriction applies where knotweed on the defendant’s land merely diminishes the claimant’s property value without physical encroachment or interference with its use and enjoyment. Non-trivial encroachment of knotweed into the claimant’s land can itself impair amenity and constitute damage; additional proof of risk to structures or development prospects is unnecessary, although trivial encroachment is not actionable. A continuing nuisance can cause continuing loss where the defendant, after knowledge and a reasonable opportunity to act, fails to treat the source of the nuisance.

The appellant owned a rented property adjoining council land from which Japanese knotweed had encroached. The District Judge found a continuing nuisance and breach of duty from 2013 to 2018, but dismissed the claim for residual diminution in value on the basis that such loss was irrecoverable under Williams v National Rail. The Circuit Judge dismissed the appeal, treating Williams as authority that knotweed-related diminution in value was pure economic loss. The appellant brought a second appeal on recoverability. The respondent defended the decision and, by respondent’s notice, challenged causation and the quality of the valuation evidence. The central issues were whether diminution in value consequential on an actionable nuisance was recoverable, whether the continuing breach caused the loss, and whether the evidence supported an award.

1. Appeal allowed; respondent’s notice dismissed. The court rejected the lower courts’ interpretation of Williams v National Rail. That decision concerned the absence of an actionable nuisance where knotweed remained on the defendant’s land and merely reduced the market value of the claimant’s land. It did not establish that economic consequences of a completed nuisance are irrecoverable.
2. Where knotweed has encroached into the claimant’s land to a non-trivial extent, its physical presence impairs the claimant’s ability to use and enjoy the land and diminishes its amenity. The examples in Williams of risk to structures and difficulty of development were illustrative, not additional conditions of liability. Trivial or de minimis encroachment would not be actionable. Consequential residual diminution in value is recoverable because it results from physical interference, rather than constituting pure economic loss.
3. The causation challenge failed. The duty was not one of strict liability: it arose from actual or presumed knowledge of the nuisance and a reasonable opportunity to abate it. The nuisance and resulting harm continued while the council failed adequately to treat knotweed on its own land. Treatment by the claimant would have been futile until the source was dealt with. This was an application of ordinary causation analysis, not an exception to the but for test.
4. The court assessed quantum itself under Civil Procedure Rules 1998, Part 52 r52.20(1), because it had the necessary powers and evidence and the parties had addressed the issue. The respondent had produced no evidence justifying a reduction of the expert’s valuation. The court awarded £4,900 for residual diminution in value.

1. Court of Appeal (Civil Division): [2023] EWCA Civ 80. Appeal allowed and the respondent’s notice dismissed.
2. County Court at Swansea: HHJ Beard dismissed the appeal on 27 May 2022, upholding the District Judge’s dismissal of the claim.
3. District Judge Fouracre, Swansea County Court: judgment given on 8 November 2021; found breach of duty from 2013 to 2018 but dismissed the claim for damages.