Can the courts assist landowners in the battle against Japanese Knotweed?

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Can the courts assist landowners in the battle against Japanese Knotweed? We look at two recent cases. 

Williams & Waistell v Network Rail Infrastructure Ltd

We previously reported on the landmark case of Williams & Waistell v Network Rail Infrastructure Ltd. The decision meant that landowners now face potential liability in nuisance to adjoining landowners for the presence of Japanese Knotweed on their land. In Williams, the County Court held that Japanese Knotweed on Network Rail’s land interfered with the claimants’ enjoyment of their own land and was therefore an actionable nuisance. The claimants were awarded damages for diminution in value of their properties and for the cost of a treatment package for the ferocious weed.

Network Rail appealed the decision, but the Court of Appeal dismissed their appeal in a decision published on 3 July 2018. The decision confirms that landowners can be liable to neighbours for Japanese Knotweed on their land. The Court of Appeal’s decision is significant as the judgment will now be binding on the lower Courts.

The Court of Appeal, however, based this decision on different reasons to the County Court. The Court of Appeal disagreed that there could be an actionable nuisance simply because the presence of the weed diminished the value of the property. It found that in the case of nuisance through the interference with land, physical damage is not necessary to complete the cause of action. However, so far as nuisance from encroachment is concerned, damage is always presumed.

The Court of Appeal went on to describe Japanese Knotweed as a “natural hazard” which affects a property owner’s ability to fully use and enjoy the land. The damage, they said, is constituted by the diminished ability of the claimants to use and enjoy the amenity of their property.

In the meantime, there has been a further County Court decision on Japanese Knotweed in which the claimants also succeeded in a nuisance claim against the owner of the neighbouring property which was plagued by Japanese Knotweed. Interestingly, however, the case also extends the ambit of available remedies for those struggling with uncooperative and inactive neighbours.

Smith and another v Line (CTR00216)

Mr and Mrs Smith purchased property from Ms Line, who retained the adjoining property. Mr and Mrs Smith later discovered Japanese Knotweed on their property and took steps to eradicate it. Their eradication programme was entirely successful and expert evidence presented in the case confirmed that there was no Japanese Knotweed remaining on the Smiths’ property. Ms Line’s property, however, was infested with Japanese Knotweed and the Smiths were legitimately concerned about this encroaching onto their land, especially as the weed was close to the boundary line. Japanese Knotweed is an aggressive and resilient weed and it can spread rapidly.

Mr and Mrs Smith asked Ms Line to take steps to get rid of the weed, but she refused to engage in any meaningful attempts to rid her property of the weed. Occasionally, some spraying or burning would take place on an ad-hoc basis, but these attempts were unsuccessful to defeat the weed. Eradication is a lengthy and difficult process and requires proper management by a reputable and experienced company.

Although the Smiths had a legitimate claim for damages, they sought a mandatory injunction to compel Ms Line to address the problem of the weed appropriately.

The Judge found that the Japanese Knotweed was a nuisance and granted a mandatory injunction requiring Ms Line to enter into a contract with a reputable contractor to treat the Japanese Knotweed on her land. She was also ordered to pay the Smiths’ costs.

It is worth noting, however, that the Judge followed the reasoning of the County Court in Williams which is now known to be incorrect in light of the Court of Appeal decision. That said, given that the Japanese Knotweed had actually spread to the claimants’ land in Smith it is likely that the claimants would still succeed in applying the Court of Appeal reasoning (notwithstanding the fact that they had treated it themselves).


The Court of Appeal have now made it abundantly clear that landowners can be liable for allowing Japanese Knotweed to grow on their land when that affects neighbouring properties, and that injunctive relief for those affected is available.

In the Williams County Court decision, the judge declined to order injunctive relief requiring Network Rail to undertake treatment of the weed. The judge concluded that it was not appropriate to grant an injunction compelling Network Rail to abate the nuisance and adequately and effectively treat the Knotweed; as such, an injunction would be vague and uncertain.

However, in Line the judge granted a mandatory injunction forcing the defendant to take appropriate steps to eradicate the weed on her land.

The Court of Appeal has confirmed injunctions as a suitable remedy in appropriate cases.

The confirmed availability of injunctions as a remedy in the fight against Japanese Knotweed is positive news for housebuilders. If Japanese Knotweed is present on adjacent land to a proposed development, damages are of little practical value. Any developed houses would be very difficult, if not impossible, to sell, rendering the land effectively worthless to any developer. An injunction requiring the offender to remove and treat the Japanese Knotweed offers much more practical value.

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