Landowners’ Liabilities in Respect of Japanese Knotweed

Lauren Parsons, Solicitor at Berry Smith, considers the liabilities of landowners in respect of the presence of Japanese Knotweed on their land. 


After the Court of Appeal’s decision in Williams v Network Rail Infrastructure Limited, it is vital that landowners are aware of their rights, responsibilities and liabilities in respect of Japanese Knotweed.  

It is often the case that landowners believe there has to be physical damage to property in order for a claim in nuisance to be made.  However, after the Court of Appeal’s decision in the above case, this is no longer the fact.

The Case

In this case, the Claimants owned property next to land owned by Network Rail. The land grew a strand of Japanese Knotweed that was known to cause significant damage if left unchecked and / or untreated. Network Rail had undertaken occasional herbicide treatment but had not implemented any plan for the removal and destruction of the Japanese Knotweed.

The Claimants initial claim was a private nuisance claim against Network Rail, which was argued on two main issues: –

  • They had a claim for encroachment as the roots of the Japanese Knotweed had spread underneath their properties; and
  • They had a claim for the loss of quiet enjoyment / loss of amenity of their properties as the Japanese Knotweed was an interference with their land. The Claimants argued the interference was sufficiently serious to enable them to bring a nuisance claim.  

Initially, the Claimants lost on the first element of their claim. It was found that in order to bring a claim for encroachment, there must be physical damage evident, which neither of the experts involved in the claim had found. Whilst it was agreed by the experts the roots of the Japanese Knotweed had spread underneath the properties, there was no evidence of actual, physical damage.

However, the Claimants were successful on the second element of their claim.  The Court decided that loss of amenity could include the loss of potential value of a property should it be marketed for sale. The Court found the presence of Japanese Knotweed was enough to diminish the value of a property.

It was also held that Network Rail had sufficient knowledge of the problem to have taken action and that they had failed to do what was reasonable to reduce the problem, resulting in the Claimants’ loss of enjoyment of their land.

Network Rail appealed the decision of the County Court.

The Court of Appeal disagreed with the initial Court’s findings. It found that, as a nuisance claim is a tort (a civil wrong that has caused a Claimant loss or damage), the purpose was not to protect the value of property as a financial asset. The Court of Appeal believed the purpose of a claim in tort was to protect the actual quiet enjoyment of the land / property itself.   

However, the Court of Appeal also disagreed that a claim in nuisance for encroachment required physical damage. The Court of Appeal believed that there was an immediate burden on a landowner who wished to develop their land, if Japanese Knotweed was present. This was due to the increased costs and difficulties in arranging for the removal and destruction of the Japanese Knotweed.

The Court of Appeal held that Network Rail had failed to act on what they knew was a potential problem, which gave rise to a claim in nuisance and they upheld the initial Court’s decision to award the Claimants damages.

The decision of the Court of Appeal will have a significant impact on landowners throughout England and Wales. The decision made by the initial Court would have meant that a landowner’s neighbour may have had an actionable nuisance claim for loss of value of a property, simply because there was Japanese Knotweed present on a neighbouring landowner’s property.

An award for loss of value of a property was not a previously recognised head of loss in a nuisance claim.

The Court of Appeal dismissed the loss of value element of the claim for this reason. However, the Court of Appeal allowed the award of damages, on the basis it compensated the Claimants for the loss of enjoyment to their property.


It is a long-established principle of nuisance claims that simply doing nothing is not a valid defence to a claim.

The Court of Appeal’s decision has ensured that landowners now need to take all reasonable steps to ensure the encroachment of any Japanese Knotweed onto neighbouring properties is prevented or, at the very least, minimised.

This will be the case even if there is no physical damage to the neighbouring property. The mere presence of Japanese Knotweed may now be considered sufficient for a claim to be made.

Therefore, it is vital that if a landowner becomes aware of Japanese Knotweed on their land, they take all reasonable steps to minimise the risks, which will usually involve seeking expert advice immediately on the removal and destruction of the plant.

Otherwise, they leave themselves open to a potential nuisance claim from a neighbouring property owner, even if no physical damage has been caused.

Lauren Parsons is a Solicitor in the Dispute Resolution team at Berry Smith

Telephone – 029 2034 5511

Email –