Network Rail Infrastructure Ltd v Williams & Anr
 EWCA Civ 1514
Stephen Williams and Robin Waistell, the Respondents, both owned homes located in front of a Network Rail (NR) track. Behind their houses, the embankment was infested with Japanese knotweed, which was estimated to have been there for 50 years. Knotweed is a hardy plant similar to bamboo, which grows extremely quickly and is renowned for its vast root structure or “rhizomes”. The plant is notorious, very invasive and requires specific treatment to remove it. A paper published in 2012 by the RICS confirmed that knotweed rhizomes have the potential to block drains; grow between slabs of concrete; disrupt brick paving; undermine garden walls; and overwhelm poorly built outbuildings.
The Respondents originally claimed that the Japanese knotweed had become a private nuisance due to its encroachment onto their properties. However, at first instance, the Recorder dismissed this claim, holding that neither side’s experts had found any evidence of physical damage. However, the Recorder did find NR liable due to the disturbance of the quiet enjoyment of both Williams and Waistell. The Recorder found that since there was a risk of future damage and mortgage lenders would not be willing to lend on properties where knotweed was present within seven metres, both Respondents had a claim for a loss of amenity. The Recorder declared that the knotweed on NR’s land had caused a loss of enjoyment to the property and awarded damages of £10,500 towards diminution of the property value and £5,000 for the cost of removing and disposing of the knotweed.
NR appealed this decision on two grounds. The first was that the mere presence of knotweed on their railway embankment could not possibly be the cause of an actionable nuisance to neighbouring properties. Secondly, that if it had indeed encroached onto the properties then the owners needed to prove physical damage had occurred to the property before NR would be liable. The Respondents replied that encroachment without physical damage can still lead to private nuisance and the mere presence of knotweed within the soil should constitute damage regardless of any physical effects.
The CA said that private nuisance could often be broken down into three categories: nuisance by encroachment, physical injury, and interference with quiet enjoyment. It is also accepted that damage is a quintessential requirement for a nuisance claim. However, the CA was also willing to accept that in previous cases of nuisance, damage was often an elastic value which can be difficult to pin down. Therefore, the CA has ruled that to suggest that the presence of knotweed in an adjoining property would not qualify as an actionable nuisance simply because it diminished the market value (due to lender caution) of the claimants' respective properties was wrong in principle. However, the CA did conclude that, once encroachment has been confirmed, this will automatically amount to physical damage and a right to compensation. Sir Terence Etherton MR said:
“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.”
This CA decision establishes that if a public body, company or freehold owner has allowed knotweed to spread within seven metres then they could be held liable for their negligence. Perhaps the biggest change is that this judgment moves the case law on for economic loss in tort. The CA further confirmed that definite physical damage may not be a fundamental requirement for a private nuisance claim. Here, simply the presence of Japanese knotweed rhizomes was enough to cause interference with the Defendants’ quiet enjoyment of their property. As a result, both Respondents were entitled to damages for the diminution of the value of their homes purely because of the presence of knotweed.
For those buying or selling property, paragraph 7.8 of the TA6 Property Information Form asks if your property is affected by Japanese knotweed. If a dishonest answer is given, your buyer can either rescind the contract or claim damages equating to the loss of value of the property.