Delaware Mansions v. Lord Mayor and Citizens of Westminster

Tree-root encroachment may remain a continuing nuisance while the roots dehydrate soil and inhibit rehydration. Impairment of the load-bearing qualities of residential land is itself damage. Fresh cracking after the claimant acquired the land is unnecessary.

Where the defendant knew or ought to have known of the continuing nuisance, the current owner may recover reasonably incurred remedial expenditure. Recovery may include elements addressing unsatisfied pre-acquisition damage and protection against future harm. As a general rule, the defendant must first receive notice and a reasonable opportunity to abate the nuisance. A tree owner who then elects to preserve the tree may fairly be required to bear the cost of reasonably necessary works. Double recovery remains impermissible.

Delaware Mansions v. Lord Mayor and Citizens of Westminster concerned structural damage caused by roots from a London plane tree owned and controlled by Westminster City Council. Most of the visible cracking had occurred before Flecksun Ltd acquired the freehold, but the roots continued to dehydrate the supporting clay soil.

After receiving notice, the council installed a root barrier but declined to remove the tree. Flecksun undertook underpinning and piling works which the trial judge found were reasonable and properly incurred. The Official Referee nevertheless dismissed the claim because the visible damage pre-dated Flecksun's ownership: (1998) 88 BLR 99.

The Court of Appeal allowed Flecksun's appeal and awarded the reasonable expenditure and interest: [2000] BLR 1. The central issue before the House was whether a current owner could recover reasonable remedial expenditure where the nuisance continued after acquisition, although most visible structural damage had occurred earlier.

Appeal dismissed unanimously. Lord Cooke of Thorndon delivered the leading speech. Lord Steyn, Lord Browne-Wilkinson, Lord Clyde and Lord Hutton agreed with his reasons.

1. Per Lord Cooke, the roots caused a continuing nuisance throughout Flecksun's ownership. They continued to dehydrate the soil and inhibit its rehydration until completion of the underpinning and piling. Impairment of the land's load-bearing qualities was itself actionable damage; fresh cracking of the building after acquisition was unnecessary.

2. The governing principles were reasonableness between neighbours and reasonable foreseeability. Drawing on Sedleigh-Denfield v O'Callaghan [1940] AC 880, Overseas Tankship (UK) Ltd v Miller Steamship Co Pty [1967] 1 AC 617 and Goldman v Hargrave [1967] 1 AC 645, Lord Cooke considered the defendant's knowledge, ability to foresee the consequences, ability to abate the hazard and the proportionality of the required response. The proximity of the tree made a real risk of damage foreseeable.

3. As a general rule, a tree owner is entitled to notice of the damage and a reasonable opportunity to abate the nuisance before becoming liable for substantial remedial expenditure. The warning against disproportionate burdens in Solloway v Hampshire County Council (1981) 79 LGR 449 was important. Westminster had ample notice and time to remove the tree before the works began.

4. Once the council elected not to remove the tree, the underpinning and piling were reasonably necessary. The owner who incurred their cost could recover it, although the expenditure included elements relating to unsatisfied damage predating its ownership and protection against future harm. This conclusion was consistent with Masters v Brent London Borough Council [1978] 1 QB 841.

5. Double recovery is impermissible. None arose because the former owner had not incurred the remedial expenditure and could not recover merely for apprehended future damage. Westminster's appeal was dismissed with costs.

• House of Lords: In Delaware Mansions v. Lord Mayor and Citizens of Westminster [2001] UKHL 55, the House unanimously dismissed Westminster's appeal with costs and affirmed the Court of Appeal's order.
• Court of Appeal: The court allowed Flecksun's appeal and entered judgment for £835,430.92, comprising the claimed expenditure and interest: [2000] BLR 1.
• Queen's Bench Division, Official Referees' Business: Mr Recorder Derek Wood QC dismissed both plaintiffs' claims, although he found that the remedial expenditure was reasonable and properly incurred: (1998) 88 BLR 99.