Japanese knotweed nuisance in the light of Waistell and Smith v Line

11 May 2018


Recent decisions on Japanese knotweed nuisance

Two recent County Court decisions have grappled with the issue of Japanese knotweed (JK) in the context of private nuisance claims between neighbouring landowners. The first was the judgment of Mr Recorder Grubb in Cardiff in respect of two separate actions with a common defendant: Williams v Network Rail Infrastructure Ltd (B20YX969) and Waistell v Network Rail Infrastructure Ltd (B34YJ849) (together Waistell). Still more recent was the judgment of HHJ Carr in Truro in Smith and another v Line (CTR00216) (Smith v Line), which was widely reported, albeit not entirely accurately, in the broadsheet and tabloid newspapers at the time of the hearing.


In Waistell, the claimants each owned half of a pair of adjoining semi-detached houses. Network Rail owned an active railway line behind those houses as well as an access path and an embankment between the houses and the railway line. JK had existed on the embankment for upwards of 50 years. The claimants alleged nuisance in two ways:

  • By physical encroachment of the JK onto the claimants’ land.
  • By the presence of JK on the defendant’s land.

Both claimants sought injunctions (requiring Network Rail to treat the JK) and damages (including for diminution in the value of the claimants’ land).

Mr Recorder Grubb held that, notwithstanding that the JK had encroached from Network Rail’s embankment, across the access path, over the boundary to (and under) the claimants’ foundations, the claimants had failed to make out their claim on encroachment. This was because the claimants had not shown damage to their land which, in the light of Lemmon v. Webb [1894] 3 Ch 1 and Delaware Mansions v Westminster City Council [2001] UKHL 55, was an essential element (at least in cases such as gradual encroachment from branches and roots in contrast to original encroachment from built projections).

However, Mr Recorder Grubb went on to hold that the claimants succeeded in establishing that the presence of the JK on Network Rail’s land had unlawfully interfered with the claimants’ quiet enjoyment or use and enjoyment of their land where:

  • (As was agreed) the value of the claimants’ land was reduced by the presence of JK on Network Rail’s land, even if treated.
  • (As was held) Network Rail had breached the measured duty of care it owed its neighbours to take reasonable steps to minimise a known hazard.

Mr Recorder Grubb declined to order injunctive relief requiring Network Rail to undertake treatment of the JK, but each claimant recovered damages of:

  • £4,320 representing the cost of a JK treatment package with an insurance-backed guarantee.
  • £10,500 and £10,000 respectively for diminution in value of their property.

Network Rail is appealing the decision.

Smith v Line

In Smith v Line, the defendant owned a large tract of beachside land. She sold a house on it to the claimants in 2002 for £200,000 retaining the majority of the land to be used for grazing and, in summer, public car parking. The claimants discovered JK on their land in 2003 and complained to Ms Line who suggested that, in fact, it had encroached from the claimants’ land onto hers. By 2013, the claimants had successfully treated the JK on their land and requested Ms Line to take steps to remove it from hers where it grew close to the boundary. Ms Line refused and repeated her assertion that it was encroaching from the claimants’ land. The claimants issued a nuisance claim seeking an injunction or, alternatively, damages. Ms Line defended the claim on the basis that:

  • The encroachment was onto her land.
  • She had, in any event, taken reasonable steps to treat it.

Joint experts were instructed who concluded that the:

  • JK had started on Ms Line’s land and encroached onto the claimants’ land.
  • Continued presence of JK, untreated, on Ms Line’s land close to the boundary with the claimants’ land had the effect of reducing the current value of the claimants’ land by 10%, from £800,000 to £720,000.

The claimants, as in Waistell, argued nuisance on the basis of:

  • Physical encroachment.
  • Interference with the amenity of their land based on the presence of JK on Ms Line’s land.

His Honour Judge Carr, in giving judgment, said that he could not improve on the judgment in Waistell and so, unsurprisingly, found that the claimant’s land had not been damaged but (having additionally found that Ms Line had failed to comply with her measured duty of care) that the JK on Ms Line’s land interfered with the claimants’ enjoyment of their land.

The learned judge:

  • Granted a mandatory injunction requiring Ms Line to enter into a contract with a reputable contractor to treat the JK on her land.
  • Ordered her to pay the claimants’ costs.


The encroachment argument

In both cases the claimants lost on the encroachment argument (but succeeded on the loss of amenity argument). In Waistell, this was a large aspect of the overall claim. But in Smith v Line, as the JK had been removed from the claimants’ land, it was relevant only to the claim for a quia timet injunction (where no wrong has yet been committed, although it is threatened).

The encroachment argument failed largely because the claimants failed to satisfy the judge that physical damage had been caused (or would be caused) to their land by the simple presence of JK. In each case it was unsuccessfully argued that the very presence of JK on the claimants’ land amounted to, or would amount to, physical damage relying by analogy with other physical damage cases: dust ground into a carpet (Pill LJ in Hunter v Canary Wharf Limited [1997] AC 655; silt on a river bed (Schiemann LJ in Jan de Nil (UK) Limited v AXA Royal Belge SA [2001] EWCA Civ 209); marshland contaminated by radioactive water overflowing from higher land (Aldous LJ in Blue Circle Industries plc v Ministry of Defence [1999] Ch 289). It remains to be seen whether the Court of Appeal, when considering Network Rail’s appeal in Waistell later in 2018 might be persuaded that land contaminated by the encroachment of perncious JK rhizomes has been damaged in the same way as land contaminated (but not to the extent to render it dangerous) by radioactive material requiring the removal of the topsoil.


Waistell and Smith v Line differed notably on the question of remedies. In Waistell, the claimants rowed back on seeking injunctive relief to enforce treatment and pressed instead for damages in lieu of an injunction together with damages for residual diminution in value. It seems an unusual approach in the absence of obtaining an order enabling the claimants to have access to Network Rail’s land to carry out the work themselves. Without such an order, or agreement, the claimants could find themselves limited to damages for the residual diminution in value of the property premised on treatment works that had not in fact been carried out. In contrast, in Smith v Line, the claimants were primarily concerned to obtain injunctive relief to effect the removal of the JK from Ms Line’s land, rather than any financial claim. They did not seek to recover the costs they had incurred in removing it from their own land, or any residual diminution which might survive the treatment.

No encroachment claim without physical damage

Subject to any Court of Appeal decision to the contrary, it remains likely that, while neither Waistell nor Smith v Line are binding authorities, any claim in nuisance based on encroachment of JK will not succeed in the absence of physical damage to the claimant’s land. That leaves potential claimants having to rely on the loss of amenity approach based on the diminution in value of their land by reason of a reduced market. Mortgage funders are likely to be less willing to lend on land with JK close to its borders. Where such claims are brought only after the JK has crossed the border, it raises the risk that a neighbour will argue that the infestation in fact began on the claimant’s land.

Problems with loss of amenity approach

The loss of amenity approach has, of course, its own difficulties. In treating the reduction in the economic value of the claimant’s land as a loss of its amenity value (equating it with the impact on use caused by smells, noises and stigma emanating from neighbouring land) it has widened the circumstances in which otherwise lawful use of land might become tortious: might it now be tortious if a neighbour keeps an unruly garden or paints his house purple if that has an impact on the value of a neighbour’s house? The Court of Appeal will likely want a treatment programme to prevent the spread of such claims.

John Clargo acted for Mr and Mrs Smith in Smith v Line.


This article was first published on Practical Law’s Property Blog.


John Clargo

Call: 1994


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