Japanese Knotweed Damages Allowed Where Use of Land Affected
Landowners including local authorities and other public bodies may be at risk of nuisance claims following the recent ruling of the Court of Appeal in Network Rail Infrastructure Ltd v (1) Williams (2) Waistell  EWCA (England Wales Court of Appeal) Civ 1514. This case concerned the liability in nuisance of a landowner where Network Rail had allowed Japanese knotweed to grow in close proximity to its neighbours’ land. This is the case even though no actual damage was caused.
The Court of Appeal found in favour of two homeowners who had sued Network Rail after knotweed from a railway embankment had spread to their properties.
The Court of Appeal went to great lengths to state that the presence of Japanese knotweed was not actionable under a nuisance claim because it had diminished the market value of the respondent’s properties. The decision means that those claiming nuisance will need to demonstrate that the nearby presence of Japanese knotweed interferes with their use and enjoyment of the land.
However, in practice, the presence of Japanese knotweed is always likely to interfere with a property owner’s use of enjoyment of the land. Furthermore, the presence of the Rhizomes, despite not causing any physical damage, was noted by the judge as being a “natural hazard”. The Judge said. “They affect the owner’s ability fully to use and enjoy the land.”
Japanese knotweed, which was described by the court as a “pernicious weed”, is a fast-growing plant which is difficult to eradicate and spreads rapidly through an extensive network of underground roots, stems or rhizomes. While the plant itself can quickly grow to a height of over two metres, the roots can extend up to seven meters horizontally and three metres vertically, affecting buildings and construction works.
Because of the potential ramifications of Japanese knotweed on the property, the Council of Mortgage Lenders (CML) has published a policy stating that it might affect the valuation of the property and might be an issue for customers whose property is affected but who cannot afford the treatment costs. The policy requires the valuers who inspect property for mortgage purposes to report on the presence of knotweed within seven meters of the property to lenders, so that they can take account of it as part of the valuation process.
Sir Terence Etherton, giving the judgment of the Court of Appeal, described a claim of private nuisance as one based on “a violation for real property rights”. This violation need not necessarily take the form of physical damage to property; however, it could not consist of merely pure economic loss.
In view of the above, to minimise risk of liability landowners and public bodies should take steps to identify if any Japanese knotweed is present on their land and then take steps to eradicate it.