Appeal update: liability for Japanese Knotweed

Network Rail Infrastructure Limited v Williams and anor [2018] EWCA Civ 1514

The Court of Appeal has confirmed that landowners faced with the prospect of Japanese Knotweed encroaching on their land are able to bring a private nuisance claim, even where there has yet to be any physical damage to their property.

Background – County Court claim

The litigation concerned the encroachment of Japanese Knotweed onto the claimants' properties from an adjoining embankment and access path owned by Network Rail. Despite accepting that the encroachment had taken place, the Judge at first instance ruled that the claimants were not entitled to succeed on the basis of encroachment alone, without some physical damage to their properties. However, the Judge accepted the claimants' claim for loss of amenity, due to the expected diminution in value and awarded damages as a result.

Court of Appeal decision

The Court of Appeal upheld the decision of the County Court, but provided different reasoning. In particular, the Court was critical of the County Court's finding that an actionable nuisance claim could arise as a result of the diminution of value of the properties. The Court of Appeal emphasised that such a conclusion was went beyond the scope of the purpose of the tort of nuisance, which is to protect the owner's use and enjoyment of their land and not its value as an investment or financial asset. However, the appeal was still dismissed on the basis that the mere presence of the Japanese Knotweed on the respondents' land immediately affected the owners' ability to fully use and enjoy their land. For example, the presence of the Knotweed would increase the likely costs of developing the land in the future.

This case has confirmed the need for landowners who have identified Japanese Knotweed on their land to take immediate action, particularly where the Knotweed is located near a boundary. They may otherwise they may be liable to their neighbours, even where no physical damage has been caused as a result. However, it remains likely that committing to undertake reasonable steps to prevent Knotweed spreading will mitigate this liability.