Berent v Family Mosaic Housing & Ors

In tree-root subsidence claims, liability in nuisance or negligence depends on whether the defendant knew, or ought to have known, of a real and reasonably foreseeable risk of damage, and failed to take reasonable steps in the circumstances to abate it. Tree roots need not be the sole cause of damage, but must be an effective and substantial cause. A protected tree remains protected unless removal or other interference is necessary to prevent or abate the nuisance. The court must evaluate all available remedial measures and the parties’ knowledge, resources and competing interests. A local authority is not subject to strict liability merely because its trees may possibly cause damage. Liability arises when the possibility becomes a real risk and reasonable abatement is not undertaken.

The claimant owned a converted Victorian house in Islington. The first defendant owned a neighbouring property and London plane tree. The second defendant was responsible for two London plane street trees. The claimant alleged that the defendants’ tree roots caused subsidence, nuisance and negligence, and sought damages and tree-removal orders.

The damage followed tunnelling works, defective drains, dry weather and vegetation. The central issues were causation, the defendants’ knowledge of a reasonably foreseeable risk, the effect of a Tree Preservation Order, the reasonableness and timing of abatement, and the recoverable loss.

1. The claim was established in part. The defendants’ London plane tree roots made an effective and material contribution to desiccation affecting the front and left-hand parts of the property. In 2003 they were not the predominant cause, but they contributed to the vulnerable condition of the soil and foundations. From 2004 onwards they became the predominant and effective cause of desiccation and rehydration.

2. Following Delaware Mansions v Westminster City Council [2002] 1AC 321 (HL), the labels nuisance and negligence did not determine the content of the duty. The question was whether the defendants acted reasonably. The relevant considerations included knowledge of the hazard, ability to foresee the consequences of inaction, and ability to abate it, assessed in the defendants’ individual circumstances.

3. The applicable foreseeability threshold was a real risk, rather than a possibility which could reasonably be disregarded. Tree roots need not be the sole cause of damage. It was sufficient that they were an effective and substantial cause, applying Loftus-Brighan v London Borough of Ealing [2003] EWCA Civ.

4. Before 2005, the second defendant had no sufficient information to establish that its trees created a real risk of damage. The first defendant was notified of a possible link in January 2005, but reasonably awaited further technical information. By 2009 or 2010, however, the risk was established and removal was the only reliable means of abatement. Failure by both defendants to remove the trees by autumn 2010 was unreasonable and constituted breach.

5. Under section 198(6)(b) of the Town and Country Planning Act 1990, a protected tree remained protected unless there was a real need to interfere with it. Following Perrin v Northampton Borough Council [2008] 1WLR 137, the court had to identify and evaluate possible means of abatement and determine whether interference with the tree was necessary.

6. The major structural damage occurred in 2003 and 2004 and was not caused by the later breach. The claimant was awarded £5,000 for gross inconvenience and loss of amenity attributable to the defendants’ breaches from autumn 2010. Recoverable remedial costs were confined to tree removal, cosmetic internal repairs and final repairs after the desiccation and rehydration cycle.

First-instance decision. No earlier judgment or appeal is stated in the judgment.