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Network Rail Infrastructure Ltd v Williams and Waistell Japanese knotweed - who is liable and for how much?

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The Court of Appeal has recently handed down a decision regarding the encroachment of Japanese knotweed onto Mr Williams’ and Mr Waistell’s bungalows from a Network Rail track. 

Japanese knotweed costs the UK annually between £160m and £200m and, prior to the Olympic Park being developed, there was an area of it the size of ten football pitches.  Japanese knotweed is an invasive weed that can not only have an impact on the enjoyment and structure of a property but also on the market value.  However, with media interest in it having grown exponentially over the past few years, there is a degree of scaremongering by the press that perhaps may be ill-founded.  Williams and Waistell were two men who each owned a bungalow backing on to a railway line.  The Japanese knotweed covered substantial parts of both their gardens. 

Williams and Waistell complained to Network Rail in 2013. In October 2013, May 2015 and October 2016 Network Rail carried out treatment to prevent further encroachment.  Two claims were advanced by Williams and Waistell in this matter; firstly that, as the occupier of the land, Network Rail was liable for the knotweed’s encroachment onto Williams and Waistell’s land.  Secondly, Williams and Waistell  argued that the presence of Japanese knotweed on Network Rail’s land was not only an interference with the quiet enjoyment of their properties, but it also influenced the amenity value of their properties as its presence affected their ability to sell them at market value or even to sell them at all. 

It was Network Rail’s position that any encroachment was de minimis (of minimum importance) and there was no substantial interference with the use and enjoyment of the land.

The county court initially found that, in respect of Williams and Waistell’s first claim, there was indeed an encroachment but it was not actionable because there was no physical damage; the knotweed was not in the foundations of the property.  Regarding the second claim, the county court found that there was an actionable nuisance because of the proximity of the Japanese knotweed and that amenity value of a property can include the ability to dispose of it at a proper value. 

The county court awarded damages to Mr Williams; and reimbursement to Mr Waistell of a survey he had commissioned. Both Williams and Waistell were awarded the full cost of treatment programmes and the monetary amount to take into account a 10% diminution in value.  What was surprising about this decision was that whilst the court awarded the full cost of a treatment programme to both Williams and Waistell, they did not give them  permission to enter onto Network Rail’s land to carry out the treatment. 


The matter was then brought before the Court of Appeal by Network Rail on two grounds; the first being that it was a claim for pure economic loss, which is not covered by the tort of nuisance, and furthermore, there was no causal link between the encroachment and the diminution. 

The Court of Appeal held the following with regard to the principles for the course of action for nuisance;

  1. a private nuisance is a violation of property rights;
  2. encroachment, interference and physical injury are merely examples of violation of property rights;
  3. the proposition that damage was always an essential requirement of the course of action was not entirely correct;
  4. nuisance can be caused by inaction or omission; and
  5. the broad unifying principle in this area was reasonableness between neighbours.

The Court of Appeal therefore held that on the first ground the appeal succeeded as the tort of nuisance does not protect the financial benefit of the property i.e. the value but it does protect the quiet enjoyment and amenity of a property; so the County Court judgement was upheld but for different reasons. The damages awarded by the Court of Appeal were for the same amount but were awarded for loss of quiet enjoyment as opposed to diminution in value (reduction in value of the property). 


If knotweed is encroaching on to your land, there is the potential remedy of an injunction, both if there is encroachment or the proximity of knotweed; and also damages where there is encroachment but not where the weed is only in the proximity of your land. You also face a potential liability if there is knotweed on your land and it spreads into neighbouring land even if it does not do any physical damage to any property.

The Court of Appeal provided financial redress to Messrs Williams and Waistell with regard to treatment of the land and compensate them for the loss of enjoyment of their property. 

With regards to treatment, whilst extensive research is currently being carried out into knotweed, whether or not you can ever truly kill it remains to be seen.  Furthermore, you can do more damage than good by attempting to cut it back yourself, as this can actually lead to it growing more rapidly.  Whilst there are a number of herbicide treatments that are around and insurance-backed policies that guarantee to eradicate “the world’s worst invasive species” (the World Conservation Union), it is important that you review exactly what these policies cover you for and for how long.

If you are worried about the presence of Japanese knotweed near to or on your land, please call a member of our Litigation team.