FREE CHAPTER from ‘A Practical Guide to the Law in Relation to Japanese Knotweed and Other Invasive Plants’ by Tom Carter


To establish a claim in nuisance, a claimant must show that the defendant owed them a duty of care, was in breach of that duty and the breach of duty caused the claimant loss.

Before getting onto those points, however, the claimant must show that there is something which is capable of being an actionable nuisance in the first place. The aim of this chapter is to consider what needs to be satisfied for a claimant to show a nuisance from the presence of Japanese knotweed.

To establish a nuisance, a claimant must show that:

There is Japanese knotweed within the boundaries of their land;

It has encroached onto their land from the defendant’s land.

Unlike claims for encroachment of tree roots, there is no need to show physical damage in order to establish a nuisance in relation to Japanese knotweed.

This was established in the leading case on liability for Japanese knotweed in the Court of Appeal’s decision in Network Rail v Williams [2018] EWCA Civ 1514.

This was a claim by two neighbours, both of whom owned houses that backed onto a railway line owned by Network Rail. There was Japanese knotweed growing on the railway embankment adjacent to their houses. At trial, the Recorder held that knotweed had encroached from Network Rail’s land onto the claimants’ land but that there was no physical damage.

The Recorder considered the three types of nuisance set out by Lord Lloyd in Hunter v Canary Wharf [1997] AC 655 at 695C:

  • Nuisance by encroachment on a neighbour’s land;
  • Nuisance by direct physical injury to a neighbour’s land;
  • Nuisance by interference with a neighbour’s quiet enjoyment of their land.

He held that on the authorities, a type 1 nuisance nevertheless required physical damage. On that basis, he held that there was no actionable type 1 nuisance.

A type 2 nuisance was never in issue because there was no evidence of physical damage.

The Recorder did find an actionable type 3 nuisance. He held that the presence of Japanese knotweed on the defendant’s land, close to the boundary with the claimants’ land, was sufficient to interfere with their quiet enjoyment of their land because it may nevertheless affect the sale price and this was an interference with their quiet enjoyment of the land.

In the Court of Appeal, the Master of the Rolls warned against a rigid categorisation of nuisance claims in this way (para 41) but to explain the decision, I will use the type 1 and type 3 analysis above. The Court of Appeal took the opposite approach to the Recorder and held that there was a type 1 nuisance but not a type 3 nuisance.

The Court of Appeal held that unlike tree roots, Japanese knotweed is in itself a hazard and that it will diminish the amenity value of land even without physical damage. On that basis, a claimant need only show the presence of knotweed on their land. At para 55 it was said:

Its presence, and indeed the mere presence of its rhizomes, imposes an immediate burden on the owner of the land in terms of an increased difficulty in the ability to develop, and in the cost of developing, the land, should the owner wish to do so. As the RICS paper observed, any improvement or alteration of the property requiring the removal of contaminated soil would require disposal of the soil either on site or, more likely, off site by special, and probably expensive, procedures. For all those reasons, Japanese knotweed and its rhizomes can fairly be described, in the sense of the decided cases, as a “natural hazard”. They affect the owner’s ability fully to use and enjoy the land. They are a classic example of an interference with the amenity value of the land.”

And at para 73:

In short, there is no reason why the legal position concerning nuisance caused by the encroachment of the branches or roots of trees should undermine the right of the claimants in the present case to claim damages for nuisance by reason of the encroachment of Japanese knotweed and its rhizomes from NR’s land.”

It should be noted in respect of the increased difficulty in developing land referred to in para 55 that there was no evidence from either of the claimants about plans to develop the land. It is the difficulty in principle that constitutes the interference.

The Court of Appeal did, however, reject the Recorder’s finding that presence of knotweed on the defendant’s land close to the boundary was enough to establish a type 3 nuisance per para 46:

The Recorder’s conclusion that the presence of knotweed on NR’s land within seven metres of the claimants’ properties was an actionable nuisance simply because it diminished the market value of the claimants’ respective properties, because of lender caution in such situations, was wrong in principle.”

This paragraph has caused confusion amongst some lawyers who have taken it as authority that a claimant cannot recover damages for diminution in value at all. This is wrong and I set out why in more detail in chapter 6 on diminution in value but for present purposes, the paragraph is clear authority that there cannot be liability in nuisance for knotweed outside of a claimant’s boundaries.

One exception to this, outside the scope of a nuisance claim, might be a claim under Article 1 Protocol 1 of the ECHR. I consider this in chapter 10.