Delaware Mansions Limited and Others v. Lord Mayor and Citizens of The City of Westminster

The House held that where tree roots encroach and cause ongoing dehydration of soil that impairs the load-bearing qualities of land, that impairment amounts to a continuing nuisance. If the defendant (here the highway authority and tree owner) knew or ought to have known of the hazard and had a reasonable opportunity to abate it, the owner who incurs reasonable remedial expenditure to eliminate the nuisance may recover that expenditure. The court applied familiar principles of reasonableness and reasonable foreseeability from nuisance and negligence jurisprudence (including Goldman v Hargrave, Wagon Mound No 2 and Cambridge Water), but emphasised that defendants generally should be given notice and a reasonable opportunity to abate before being made liable for large remedial bills. On the facts Westminster had notice and opportunity and was therefore liable for the reasonable underpinning and piling costs incurred by Flecksun.

Background and parties. The claimants were Delaware Mansions Ltd (a management company) and Flecksun Ltd (freehold purchaser of the block). Westminster City Council owned and controlled a plane tree in the pavement whose roots caused desiccation and subsidence beneath parts of Delaware Mansions. Flecksun acquired the freehold from the Church Commissioners in June 1990. After reports and surveys, remedial works (underpinning and piling) were carried out between January and July 1992 at a cost accepted as reasonable by Westminster.

Procedural history. The Official Referee dismissed the plaintiffs' claims (reported (1998) 88 BLR 99). The Court of Appeal allowed Flecksun's appeal and awarded judgment for the expenditure and interest (reported [2000] BLR 1). Westminster obtained leave to appeal to the House of Lords.

Issues. (i) Whether remedial expenditure incurred after tree-root encroachment is recoverable by a current owner if the damage principally occurred before transfer, (ii) whether the encroachment constituted a continuing nuisance, (iii) what role foreseeability, knowledge and reasonableness play in fixing liability, and (iv) whether the defendant should be given notice and an opportunity to abate before liability for large remedial costs arises.

Reasoning and decision. The House analysed the principles of nuisance, emphasising reasonable foreseeability and the reasonable-man standard drawn from leading authorities. It concluded that ongoing dehydration of subsoil caused by encroaching roots is itself a continuing nuisance even if visible superstructural cracking largely manifested earlier. Reasonable remedial expenditure to eliminate that nuisance may be recovered where the defendant knew or ought to have known of the hazard and had a fair opportunity to abate. The court noted Solloway v Hampshire as a caution that unreasonable burdens should not be imposed on tree owners or local authorities and therefore required notice and opportunity to abate in general; on the facts Westminster had ample notice and time and so was liable. The House dismissed Westminster's appeal.

Appeal dismissed. The House held that encroaching tree roots that dehydrate soil and impair load-bearing qualities constitute a continuing nuisance; where the defendant knew or ought to have known and had a reasonable opportunity to abate, reasonable remedial expenditure incurred by the owner to eliminate the nuisance is recoverable. The council had notice and opportunity and was therefore liable for the reasonable underpinning and piling costs incurred by Flecksun.

Official Referee (Recorder Derek Wood QC) dismissed the claims (reported (1998) 88 BLR 99). On appeal the Court of Appeal allowed Flecksun's appeal and awarded judgment for the claimed expenditure plus interest (reported [2000] BLR 1). Leave to appeal to the House of Lords was granted and the House of Lords dismissed the council's appeal ([2001] UKHL 55).