Amenity value – not diminution in value
 EWCA Civ 1514
Network Rail was liable in private nuisance (i.e. by reason of an unlawful interference with the claimants’ amenity right to enjoy their respective properties) for failing to take reasonable steps to prevent Japanese knotweed on its land from blighting domestic properties next to its railway embankment, but not for diminution of market value (which would have been pure economic loss). The purpose of the tort of nuisance was not to protect the value of property as an investment or a financial asset. Its purpose was to protect the owner of land (or a person entitled to exclusive possession) in their use and enjoyment of the land.
The claimant freehold owners of two adjoining semi-detached bungalows issued claims in private nuisance against Network Rail (“NR”) on the basis that Japanese knotweed growing on NR's land had caused damage to their properties. It was accepted that Japanese knotweed had been present on NR’s land for approximately 50 years. Each sought an injunction to require NR to treat and eliminate the knotweed on its land and damages under various heads of loss. NR defended on the basis that both claimants had failed to establish that the necessary elements of a cause of action in private nuisance were made out on the facts.
The Recorder found that:
- NR had actual knowledge of the presence of Japanese knotweed on its land behind the claimants' respective bungalows in 2013;
- NR was, or ought to have been, aware of the risk of damage and loss of amenity to adjoining properties caused by the close proximity of knotweed no later than some time in 2012 with the publication of the Environment Agency’s code of practice and the RICS paper; and
- NR failed reasonably to prevent the interference with the claimants' enjoyment of their properties.
It was further found that Japanese knotweed rhizomes had encroached on the land of each of the claimants and under their respective bungalows. He rejected the submission by NR that the encroachment was a trivial or de minimis interference with their respective properties. However, he also rejected the claimants' claim in nuisance based on that encroachment as neither expert identified any actual damage to the properties.
First instance decision
The recorder found in favour of both claimants, although injunctions were not granted. NR appealed on the ground that the recorder had erred in concluding that, where a residential homeowner suffered a diminution in the value of their property by virtue of the presence of Japanese knotweed, the pure economic loss which was suffered constituted an actionable private nuisance on the basis that it interfered with the quiet enjoyment of their property.
The Recorder's analysis was that the gist of nuisance was the objective loss of amenity in the affected property; the amenity value of a property could include the ability to dispose of it at a proper value and that value was affected where the claimed nuisance produced a blight upon the property that left the owner with uncertainty that the property may no longer be the valuable asset that it was thought to be. Accordingly, the claimants' properties had been devalued by the presence of Japanese knotweed on NR's land and, even if treated, their saleable values were below what would otherwise have been their market value despite the experts agreeing there was no physical damage. Thus, the presence of Japanese knotweed on NR's land was capable of being a private nuisance because the presence of the knotweed has unlawfully interfered with the claimants' “quiet enjoyment” or “use and enjoyment” of their respective properties.
Where a residential homeowner suffers a diminution in the value of their property by virtue of the presence of Japanese knotweed, whether the pure economic loss which was suffered constituted an actionable private nuisance on the basis that it interfered with the quiet enjoyment of their property.
Decision on appeal
The Recorder's conclusion that the presence of knotweed on NR's land within seven metres of the claimants' properties was an actionable nuisance simply because it diminished the market value of the claimants' respective properties, because of lender caution (as referenced in publications by the Counsel of Mortgage Lenders and guidance from RICS) in such situations, was wrong in principle.
The purpose of the tort of nuisance was not to protect the value of property as an investment or a financial asset. Its purpose was to protect the owner of land (or a person entitled to exclusive possession) in their use and enjoyment of the land as such as a facet of the right of ownership or right to exclusive possession. The decision of the Recorder in the present case extended the tort of nuisance to a claim for pure economic loss in such a way that it was not an incremental development of the common law by way of analogy but a radical reformulation of the purpose and scope of the tort.
However, there was no reason why, in appropriate circumstances, a claimant should not be able to obtain a final mandatory injunction where the amenity value of the land was diminished by the presence of roots, even though there had not yet been any physical damage. Further, there was no reason why the legal position concerning nuisance caused by the encroachment of the branches or roots of trees should undermine the right of the claimants in the present case to claim damages for nuisance by reason of the encroachment of Japanese knotweed and its rhizomes from NR's land.
Japanese knotweed and its rhizomes were a "natural hazard" which affected the owner's ability fully to use and enjoy the land. The Recorder's findings of fact in relation to NR’s knowledge of the presence of Japanese knotweed and its failure reasonably to prevent the interference with the respondents' enjoyment of their properties were sufficient, on the general principles (as below), to give rise to a cause of action in nuisance. Accordingly, there was no reason why the claimants should not be able to argue and succeed on the ground of an unlawful interference with their enjoyment of the amenity of their properties due to the impairment of their right to use and enjoy those properties.
The well-established general principles of nuisance: -
First, a private nuisance is a violation of real property rights. That means that it involves either an interference with the legal rights of an owner of land, including a legal interest in land such as an easement and a profit à prendre, or interference with the amenity of the land, that is to say the right to use and enjoy it, which is an inherent facet of a right of exclusive possession (Hunter v Canary Wharf Ltd  AC 655, 687G—688E).
Secondly, although nuisance is sometimes broken down into different categories, these are merely examples of a violation of property rights. The difficulty with any rigid categorisation is that it may not easily accommodate possible examples of nuisance in new social conditions or may undermine a proper analysis of factual situations which have aspects of more than one category but do not fall squarely within any one category, having regard to existing case law.
Thirdly, the frequently stated proposition that damage is always an essential requirement of the cause of action for nuisance because nuisance is derived from the old form of action on the case must be treated with considerable caution. It is clear both that this proposition is not entirely correct and also that the concept of damage in this context is a highly elastic one. In particular, interference with an easement or a profit à prendre is actionable as a nuisance without the need to prove specific damage (Harrop v Hurst (1868-69) LR 4 Ex 43, 46-47, 48; Nicholls v Ely Beet Sugar Factory Ltd  Ch 343, 349-350). It is also well established that, in the case of nuisance through interference with the amenity of the claimant's land, physical damage is not necessary to complete the cause of action. What is relevant is the objective effect on the amenity value of the land itself, and it is that effect which satisfies any requirement there may be to show damage. Provided, by reference to all the circumstances of the case and the character of the locality, and according to the objective standards of the average person, the interference with amenity is sufficiently serious, there will be an actionable private nuisance.
Fourthly, nuisance may be caused by inaction or omission as well as by some positive activity. An occupier will be liable for continuing a nuisance created by another person if, with knowledge or presumed knowledge of its existence, he or she fails to take reasonable means to bring it to an end when they had ample time to do so (Sedleigh-Denfield v O'Callaghan  AC 880, 894). An occupier will also be liable if he or she fails to act with reasonable prudence to remove a hazard, whether natural or man-made, on their land of which he or she was aware and where it was foreseeable that it would risk damaging their neighbour's land and goes on to do so (Goldman v Hargrave  1 AC 645; Leakey v National Trust For Places of Historic Interest or Natural Beauty  QB 485).
Finally, the broad unifying principle in this area of the law is reasonableness between neighbours (real or figurative): (Delaware Mansions (supra) at  and ).