A knotty problem
Railway embankments and cuttings play host to a vast array of flora including many ornamental plants which have long since escaped from the confines of neighbouring gardens. In summer they are festooned with the purple cones of buddleia flowers providing splashes of colour for the benefit of weary commuters gazing idly through the dusty windows of urban stopping trains. A far less welcome inhabitant of railway land, however, is the notorious Japanese Knotweed (Fallopia Japonica) which was first commercialized as an ornamental plant in this country in the mid-nineteenth century. It quickly escaped the confines of gardens and has steadily spread ever since.
The species is incredibly invasive and it spreads by sending out roots and rhizomes which spread deep in the soil before sending up shoots which have been reported as having the capacity to smash through concrete and tarmac, although some have argued that the threat has been exaggerated. Whatever the extent of the risk there is no doubt that the mere presence of the plant causes a serious blight problem for property.
Railway embankments and cuttings are not cleared of excessive vegetation as regularly as they used to be. At one time regular clearances were necessary to reduce the risk of lineside fires caused by stray sparks from passing steam trains. Such fires often spread to neighbouring property and resulted in vast amounts of litigation. It is possible that, after the last scheduled steam service departed on 11 August 1968, officials in British Railways may have expressed relief at the fact that there would no longer be any need to expend so much time and effort in clearing vegetation from the lineside. Anyone expressing such sentiments could not have anticipated that the change in policy may have contributed to the replacement of railway sparks with a new peril of a more organic nature.
Williams v Network Rail Infrastructure Ltd
Japanese Knotweed has inevitably spread from railway land to neighbouring property and, somewhere in the offices of Network Rail, it is reasonable to assume that there must be an increasingly fat file of complaints. Two such complainants are Robin Waistell and Stephen Williams, both of whom own neighbouring properties in the Welsh town of Maesteg in close proximity to an embankment overrun with the plant. It was estimated that the plant established itself there about 50 years ago but had been contained until more recent times. The complainants met resistance when they first sought compensation from Network Rail regarding the incursion of the plant on their land. They alleged that it had infiltrated the foundations of their bungalows and slashed the value of their properties. The media reported that, hitherto, Network Rail had met claims out of court but, due to concern at the steadily growing number of complaints and the amount that it was having to pay out, decided to make a stand in order to establish that it was not liable as a matter of law: see MailOnline. Thus messrs Waistell and Williams found themselves locking horns with Network Rail in litigation: Williams v Network Rail Infrastructure Ltd (also know as Waistell v Network Rail Infrastructure Ltd)  UK CC (2 February 2017) (unreported).
Damage to property?
The matter was tried at the Cardiff County Court, before His Honour Judge Grubb, where argument turned upon two strands of the law of private nuisance. The first strand focused on the encroachment cases as exemplified by the cases of Lemmon v Webb  3 Ch 1 and Delaware Mansions v Westminster City Council  UKHL 55;  1 AC 321, both of which were cited in argument. On this issue it was held that actual damage to property was needed in order to establish liability on this ground. The judge did not accept that the foundations had actually been damaged and the mere encroachment of the roots and rhizomes into the foundations would not suffice.
Loss of amenity
The second strand of nuisance law focused on loss of amenity value caused by proximity to some undesirable land use. Here it was noted that in the past damages had been awarded in nuisance in respect of the deleterious effects of brothels and sex shops on the amenity value of neighbouring properties. This approach circumvented the need to show actual physical damage to the fabric of the property. The claimants argument on this basis was successful, however, it was also necessary to show the harm was foreseeable and in this respect the defendants were deemed to have had constructive knowledge of a document produced by the Royal Institute of Chartered Surveyors and the Property Care Association which set out guidance on the management of the Knotweed problem.
Continuing the nuisance
There was a final complication in this case stemming from the fact that Network Rail had not set out to cultivate the plant or consciously brought it onto its land. However, once an undesirable element establishes itself on land there is a clear duty to do something about it else one is deemed to have adopted the nuisance: see Leakey v National Trust  QB 485. In this respect an element of fault is inserted into the equation and nuisance operates rather more like negligence than a tort of strict liability. Nevertheless, the judge was persuaded that the defendant had failed to act as a reasonable land owner and take sufficient steps to remove the Knotweed. There had been some inadequate and sporadic spraying with herbicide which in no way sufficed to discharge the duty.
Damages were awarded to both claimants in respect of the diminution in the market value of their properties and the cost of a treatment package and an associated insurance backed guarantee.
This was not the end of the story however and the matter has been appealed to the Court of Appeal which is due to hear the case in the New Year. The grounds of appeal are not clear from material readily available in the public domain although it would be difficult to contest the notion that Knotweed blights property even where no physical damage is caused. One can surmise that attention is likely to focus on the assertion that the defendant could have foreseen the problem and that it failed to take reasonable steps to abate it.
The case seems to have attracted a lot of media attention and the implications for property owners, mortgage providers and the insurance industry are clear. See, for example, The Telegraph (Money and Banking).