Landowner held responsible for spread of Japanese knotweed in landmark Court of Appeal case

Landowners should take reasonable steps to prevent the encroachment of Japanese knotweed onto their neighbours’ property according to a recent decision of the Court of Appeal. The decision also has important consequences for homeowners selling their property. Sophie Upton examines the landmark case of Williams v Network Rail Infrastructure Limited.

Most lenders will now agree to lend even if the property is infected by the plant as long as there is a management plan in place

Japanese knotweed has received some damning media coverage over the past few years and rightly so. The damage caused by the bamboo-like plant comes from the roots, (or "rhizomes"), which can grow up to 20cms a day and have been found at depths of three metres. It can block drains, ruin paving and overwhelm conservatories. On top of this, the plant is notoriously difficult to eradicate.

As a result, banks and building societies have been cautious about lending on properties affected by the plant, which in turn has had a negative impact on their value. The situation can be particularly frustrating for homeowners when it is their neighbour's land that is infested as they are unable to take steps to control the spread of the plant.

Claim in the Cardiff County Court

This was the situation the owners of two adjoining bungalows, Stephen Williams and Robin Waistell, found themselves with Network Rail, who owned the land to the rear of their properties in Maestag, South Wales. Network Rail's land contained a large stand of Japanese knotweed and Mr Williams and Mr Waistel brought a claim against them in the Cardiff County Court claiming that:

  1. The rhizomes had encroached underneath their properties;
  2. They had suffered a nuisance on the basis that the knotweed interfered with the quiet enjoyment and amenity value of their property.

The county court rejected the claim for encroachment on the grounds that although the knotweed had encroached, it had not caused any physical damage. But the court accepted the quiet enjoyment/loss of amenity claim on the basis that it was a stigma that affected the value of the property and this blight caused the owner to suffer a loss of enjoyment. The court concluded that Network Rail had not taken reasonable steps to prevent or minimise the nuisance and awarded each homeowner damages of £15,000.

Court of Appeal decision

Network Rail took the case to the Court of Appeal, which decided against them and upheld the award of damages. However, in doing so the Court of Appeal relied on different reasons to the county court.

The Master of the Rolls Sir Terence Etherton said in his Court of Appeal judgment that he agreed that Network Rail's failure to prevent encroachment of the rhizomes onto the claimants' land was a nuisance. However, this should not entitle the claimants to damages for economic loss (i.e. the investment value of their property) but damages for the loss of the amenity of their property (i.e., its use and enjoyment).

"It is fair to describe Japanese knotweed as a natural hazard which affects landowners' ability fully to use and enjoy their property and, in doing so, interferes with the land's amenity value. However, homeowners will not be entitled to seek damages on the grounds that the knotweed had reduced the value of their properties," he said.

The Court of Appeal decisions therefore clarifies that homeowners can only claim against neighbours whose knotweed encroaches on their land for its effect on the amenity value of the property and not any reduction in the value of the property.

The Court of Appeal also said the county court was wrong to dismiss the claim for encroachment saying it was not necessary for there to be actual physical damage for this to be established. This encroachment, said Sir Terence, was "a classic example of an interference with the amenity value of the land".

What does this mean for landowners?

The good news is that the mere presence of Japanese knotweed on your land cannot make you liable for a nuisance claim from your neighbours. The less good news is that if you do have it, you need to take reasonable steps to prevent its encroachment onto their land.

The decision also has implications if you are selling land with Japanese knotweed. The Law Society protocol forms gives the seller the opportunity to declare Japanese knotweed to any prospective buyer. In fact, it is illegal not to declare this information. Therefore, it is imperative that sellers completing these forms are cautious with their responses to ensure they do not provide any misleading information.

Knot very recognisable…

This is all well and good except for the fact that a recent survey found that only 19% of people asked were able to identify the invasive plant. This leaves the opportunity for up to 81% of people to potentially sell their property without any knowledge of their illegal behaviour.

Looking to the future…

Most lenders will now agree to lend even if the property is infected by the plant as long as there is a management plan in place. In the meantime, researchers continue to try to discover ways to eradicate it and understand its workings. Interestingly, a recent study at Leeds University with engineering firm Aecom found "no evidence" of Japanese knotweed posing anymore of a problem than trees, climbers and other shrubs". Perhaps it's not such a knotty problem after all.

If you have any further queries, please contact Sophie Upton at [email protected]