Image of Japanese knotweed
14/06/2018by Joanna Gent

Japanese knotweed

Japanese knotweed can cause a number of problems to include damage to buildings caused by the spread of its roots and issues affecting the value of and ability to sell the property as well as  insurance. There has been some recent case law on this topic to include a case brought by land owners (Waistell and Williams) against Network Rail Infrastructure Ltd (‘Network Rail’) leading to Network Rail being liable to neighbouring property for loss of enjoyment, property damage and the cost of removal of the Japanese knotweed.


In the Network Rail case, the claimants’ properties abutted a railway embankment and access path owned by Network Rail, where Japanese knotweed had been present for many years. The knotweed spread underneath the claimants’ homes and the claimants alleged that Network Rail were liable to compensate them for the encroachment of the knotweed onto their land and for the presence of the knotweed. The claimants were successful, even though the court found no physical damage had been caused to their properties.  The Court held that the presence of the knotweed interfered with the quiet enjoyment and amenity value of the claimants’ homes, as they were unable to sell their properties for their full market value. The Court found that Network Rail had failed to carry out its obligation to eliminate the problem and to prevent interference with the quiet enjoyment of the claimants’ land. The claimants were awarded damages for the cost of treatment programmes and insurance-backed guarantees, the reduction in value of their properties once treatment had taken place and damages for loss of amenity and interference with quiet enjoyment of their property.


Network Rail has appealed the Court’s decision and the appeal is due to be heard this year.


In another case (Smith v Line), there was an argument as to on whose land the knotweed first grew and the claimants issued a nuisance claim seeking an injunction or alternatively damages. Mrs Line defended the claim arguing that the encroachment was actually onto her land and that she had taken steps to treat it. The Court held again that there was no actual physical damage but that the Japanese knotweed on Mrs Lines’ land did interfere with the claimant's enjoyment of their land and granted an injunction requiring Mrs Line to instruct a reputable contractor to treat her land and ordered that Mrs Line pay the claimant’s costs.


These decisions could cause difficulties in that it might now widen what constitutes a nuisance, for example if a neighbour keeps an unruly garden or paints a house a lurid colour, as this may have a detrimental impact on the value of a neighbour’s house.


Update on Japanese Knotweed cases


In a much-anticipated judgment, the Court of Appeal clarified that an action in nuisance for diminution of value caused by Japanese knotweed is not possible as this would be an action for pure economic loss, but that Japanese knotweed can form the basis of an actionable nuisance before it causes physical damage to neighbouring land.


This will concern landowners (including public bodies owning railways, roads and rivers) who may have Japanese knotweed or other invasive non-native species on their property, particularly near borders with neighbours.


Our dedicated team of Property lawyers at ELS can help advise and support you with such situations and guide you through these many pitfalls when dealing with disciplinary matters.


If you subscribe to the ELS helpline please call 0333 013 9993 or alternatively use the contact details below.


Joanna Gent 

Legal Services Manager (Property) 

T: 0333 013 1036

Julie Roberts

Legal Services Manager (Property)

T: 0333 013 9689




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