Supreme Court to hear appeal of ruling that Council must pay Japanese knotweed damages
The Supreme Court has granted permission to appeal the decision in Davies v Bridgend County Borough Council  EWCA Civ 80, which overturned lower court rulings that found diminution in value in Japanese knotweed cases was irrecoverable economic loss and ordered the council to pay damages to a property owner.
The property owner in the case purchased a house in Nant-y-moel in 2004 as an investment but later found that Japanese knotweed, which had been growing on an adjacent plot owned by the local authority, had spread onto his property.
Claim in nuisance against the council
Mr Davies then brought a claim in nuisance against the council, which was heard before District Judge Fouracre in Swansea County Court. At that hearing, the court established that it was likely that the plant had spread from the council land and onto his property before he bought the house.
The local authority contended that since the knotweed was already present on Mr Davies’ land, any damage arose before the breach of duty, and so since the fact the property is affected by knotweed is not due to any breach, the claim was fatally flawed on causation.
The district judge concluded that the council was in breach of the relevant duty in nuisance owed to the appellant as a neighbour, starting from 2013 and on until 2018, when a treatment programme finally started.
Damages for “residual diminution”, also called “blight”,
Damages for “residual diminution”, also called “blight”, were then claimed for £4,900. However, the district judge dismissed the claim, holding that all the diminution in value damages were irrecoverable in law in a case like this, based on the decision of the Court of Appeal in Williams v National Rail  EWCA Civ 1514,  QB 601.
The property owner then appealed this decision, arguing that the damages were losses consequential on the nuisance found.
This appeal was dismissed by HHJ Beard, who accepted that the diminution in value claimed was consequential on the nuisance identified by the previous court but concluded that Williams was the authority for the proposition that damages for diminution in value due to knotweed are irrecoverable in nuisance.
A second appeal was then lodged, which solely contended that the previous judges had erred in that they had misunderstood Williams and that Williams was not an authority against the appellant’s case.
The Court of Appeal clarified that Williams did not hold that any encroachment of knotweed into the claimant’s land amounts to material interference with quiet enjoyment or amenity and actionable nuisance.
The claimant’s quiet enjoyment or use of the land
However, it emphasized that once the natural hazard of knotweed is present on the claimant’s land to a non-trivial extent, it diminishes the claimant’s quiet enjoyment or use of the land, thereby constituting damage for the purposes of the tort of nuisance.
Ultimately, the court ordered the council to pay £4,900 in damages for the residual diminution in value suffered by the property owner.
Confirming the grant of permission to appeal, St John’s Chambers’ Matthew White, who appears for Bridgend, said the issue the Supreme Court would consider was “whether a defendant is properly held responsible for residual diminution in value when a claimant’s property had already been affected by (value diminished by) Japanese knotweed before breach”.