72.The roundtable discussion that we held with individuals affected by Japanese knotweed when buying and selling their property underlined the difficulties that could be caused by reactions to the plant. This includes disrupted sales, diminished property value, and extended legal processes. One of our participants described their experience for us:
Our property had been valued at £340,000 and we quickly realised that it now had a value of zero as no surveyor would advise a bank to lend on a property with untreated Japanese knotweed. Our potential buyers withdrew from the purchase—we expected this would happen. […] We then decided to have the Japanese knotweed excavated. The work and associated guarantees cost approximately £10,000. This was an incredible amount of money for us to have to find.
[…] We then found ourselves in a position of becoming landlords at our Japanese knotweed property [due to being unable to sell it]. This is something we had never intended to do and now means we have the responsibility of acting as a landlord, something we never wanted. […] We are not ‘typical’ buy to let landlords but a family that has been forced into this position—accidental landlords.
The whole process has been time consuming, expensive, stressful and unnecessarily prevented another family from buying our home—blocking the market. […] The whole thing has been blown out of proportion. My house is a terrace built in the 1920s—there was no way a small plant had done or would do any damage to it at all.
73.Similarly, Environet UK Ltd (a Japanese knotweed remediation firm) argued that “the significance of the human cost inflicted by Japanese knotweed should not be underestimated. We frequently have customers in tears and unable to sleep”.
74.We explored with witnesses whether there was a need for changes to existing legislation (see Box 1 for examples of current legislation) or new laws regarding Japanese knotweed. While some of the people we spoke to who had been involved in neighbour disputes argued that there was a need to introduce a duty to treat Japanese knotweed, the consistent message we got from others was that further legislation would be unhelpful. For instance, Advanced Invasives argued that:
Additional legislation on the knotweed issue, particularly any suggestion that treatment of knotweed should be mandatory in all instances, irrespective of its actual impacts, is unnecessary and would further exacerbate the impacts on homeowners, despite the good intent of such legislation.
75.Similarly, Professor Wade argued that new legislation was not needed since in many cases the presence of Japanese knotweed should not be considered to be a problem.
76.Advanced Invasives summarised that the range of legal controls was a “patchwork” which was “confusing” and “lacks harmony”, adding that:
Overall, the effect of legislation, and the recent court cases centred on knotweed liability, is to increase the costs and risks arising from knotweed treatment programmes. For large landowners and public bodies in particular, undertaking effective knotweed treatment at the strategic scale, whilst minimising legal liability, is especially difficult without an authoritative and coherent source of scientifically valid treatment recommendations.
77.Environet UK Ltd was also not in favour of changing the law in this area, arguing instead that:
Lending policies are perhaps the largest force motivating homeowners to tackle their Japanese knotweed. It is a far more powerful force than any blunt Statutory Instrument, which would be both difficult and costly to enforce.
78.We were also alerted to the potential use of community protection orders as a mechanism for ensuring that knotweed causing a nuisance was treated. A Home Office factsheet explains that:
The community protection notice can be used against individuals who are acting unreasonably and who persistently or continually act in a way that has a detrimental effect on the quality of life of those in the locality. The Anti-social Behaviour, Crime and Policing Act 2014 does not explicitly refer to Japanese knotweed or other, similar invasive non-native plants, as the new anti-social behaviour powers are intended to be flexible. However, frontline professionals can stop or prevent any behaviour that meets the legal test in the powers.
79.The Chartered Institute of Ecology and Environmental Management provided a useful example of this being used in practice:
Bristol City Council brought a case against MB Estate after it ignored a Community Protection Notice served by the Council in May 2017 requiring the company to remove an infestation of Japanese knotweed from a house in Horfield. The Council had received complaints from people at seven properties neighbouring the house. The company was fined £18,000 under the Anti-Social Behaviour, Crime & Policing Act 2014 at Bristol Magistrates’ Courts on 4 December 2018. As well as the fine, the court ordered MB Estates to hire a specialist company to draw up a plan within 28 days to tackle the knotweed.
80.A common theme from the people that we spoke to who had been affected by Japanese knotweed was the difficulties arising from the plant being present on a neighbour’s property rather than their own. In these cases, the plant might be within seven metres of their building or property boundary, and yet not within their direct control. The Knotweed Company Ltd explained that in some cases access to the neighbouring property was not possible or was refused, and that they had experience of “tenants or neighbours refusing access for us to make treatments using herbicides as a result of misleading press articles”.
81.Charles Lyndon Solicitors provided some further detail on this problem:
A homeowner cannot treat neighbouring land without the agreement of the neighbouring landowner, to do otherwise would amount to trespass. This means there are a number of situations where homeowners have no way of treating the Japanese knotweed so as to allow their property to be appropriate security for a mortgage and have no legal route to force their neighbours to do so.
They summarised a case that they had worked on that illustrated this problem:
There is Japanese knotweed on her property and her neighbour’s property, [but] because of the steepness of the garden it is impossible to dig out the Japanese knotweed without causing serious damage to structures. The Japanese knotweed on both properties is very established and experts cannot determine where it originated. The client has herbicide-treated her property and offered to treat her neighbour’s property but her neighbour refuses to allow her to do so as she is concerned about the impact of the chemicals on her grandson’s health. The client cannot have her treatment guaranteed unless her neighbour also treats so she has been unable to sell her house.
82.Case law is developing in this area which provides a means of recourse. Charles Lyndon Solicitors explained that:
Under the law of private nuisance, an occupier of land (A) owes duties to occupiers of neighbouring land (B) with regards hazards occurring on A’s land. It is accepted law that if Japanese knotweed encroaches from A’s Land to B’s Land and A does not abate the nuisance (in practice by treating the Japanese knotweed on both A’s land and B’s land), B will be able to bring a claim for an injunction compelling A to treat and for damages. However, the situation is difficult where the Japanese knotweed on A’s land has not encroached onto B’s land (and there is no imminent threat of it doing so) but is within seven metres of B’s property either because it has not encroached for some reason or there is no land for it to encroach onto which may often be the case for owners of flats who do not own any garden.
83.Several of our witnesses told us about the difficulties that this route caused for homeowners. Sean Hathaway described taking legal action against a neighbour on the basis of nuisance was “quite a long, messy process”, and Stephen Hodgson from the PCA agreed that “the only real recourse for somebody living next to anyone with rampant Japanese knotweed is through the civil courts […] and that way lies chaos. We should not be in a position whereby we promote neighbour disputes in that way”.
84.John Baguley, representing RICS suggested that alternative approaches might make the process of resolving disputes easier:
I do not know whether there is a tribunal scenario or some kind of halfway house, but it is about thinking about speed of enforcement, ease of redress and how you achieve that. The court system obviously works, but for the average person in the street to go through the court system is hard work.
85.Advanced Invasives highlighted a particular issue where the neighbour in question was Network Rail:
Knotweed may fall within the seven-metre proximity, yet homeowners will lack the access rights needed to arrange for treatment. On railway land in the UK, which is almost all managed by Network Rail, this is especially problematic; nationwide there is a large habitat often abutting private homes and this space is prone knotweed invasion.
86.In 2018, two homeowners in south Wales successfully claimed damages in the County Court against Network Rail for allowing Japanese knotweed to encroach on their property. The County Court judgment was upheld by the Court of Appeal, but on different grounds: a claim in private nuisance will not succeed just because of a reduction in the value of the claimant’s property; however, it can succeed if the encroachment of knotweed, which can be described as a “natural hazard”, reduces the claimant’s ability to enjoy “the utility and amenity” of the property—that is, making it more difficult for them fully to use and enjoy the land. Details of the case were presented to us by Charles Lyndon Solicitors. The Law Society told us that “this ruling could act as a significant precedent and encourage litigation, particularly if a property is blighted by Japanese knotweed threatening to encroach from neighbouring land”. Stephen Hodgson, representing the Property Care Association, explained that he understood that Network Rail had “learned a great deal from the case in south Wales and is engaging with homeowners and landowners when there are potential neighbour issues”.
87.The Law Society also noted that “if scientific studies demonstrate that Japanese knotweed is not as pernicious as thought, then the basis for this appeal court ruling may be subject to challenge or could reduce the risk of litigation”. Given that the conclusion of the latest research seems to be that the physical impacts of the plant are not as extreme as previously thought, this could leave homeowners in an unclear position.
88.Our discussions with individuals affected by Japanese knotweed who had experience of Network Rail identified the problem of the company not allowing recognised contractors to access their land for safety reasons, meaning that even when the plant was treated by Network Rail this was not recognised by mortgage lenders. Again, Charles Lyndon Solicitors provided a case study of this:
The client offered to treat Network Rail’s land, but they refused as they will not allow anyone other than their own contractors onto their land. This commonly happens with corporate or institutional landowners including local councils. She discussed the possibility of paying their contractors to treat the Japanese knotweed but, as their contractors are not a PCA registered firm, this would not solve the problem. The client is therefore unable to sell her small flat to buy a home with her husband.
89.We wrote to Network Rail to ask them to clarify its position on this issue and suggest how this could be better resolved. Network Rail explained the actions it took to manage Japanese knotweed when it was identified on its land so as to stop it spreading to other parts of railway land and neighbouring properties. In March 2019, Network Rail told us that in the 2018–19 financial year so far it had treated “approximately 600,000 square metres of Japanese knotweed. At an average treatment cost of £2 per square metre, this equates to around £1.2m”.
90.It also set out its treatment approach and the associated challenges relating to assurances sought by mortgage lenders:
Our treatment methods are in line with the guidance published by the Environment Agency, as well as wider industry standards. As your letter correctly identifies, however, this work can only be carried out by our own teams or by approved contractors for safety reasons.
While our suppliers and route teams are, of course, obliged to comply with the standards I mentioned above, they are currently unable to issue either insurance backed guarantees or an alternative equivalent formal assurance that Japanese Knotweed has been treated to the standard that mortgage lenders require.
91.Network Rail acknowledged that the current situation was difficult for homeowners but explained that it could not meet the required mortgage lender standards as it, as a public sector organisation operating to managing public money guidelines, would be “unable to justify the additional cost that would be incurred by requiring our contractors (where they carry out this work) to provide insurance backed guarantees for the treatment”. Network Rail also explained that it had arranged a meeting with the Property Care Association to discuss these challenges later in March 2019. The PCA and Network Rail explained that this meeting was held and that the challenges faced by Network Rail were discussed and a proposal to address them suggested. Subsequent to the meeting “discussions between PCA and an insurance provider took place […] confirming a method of delivering insured guarantees could be negotiated”. Network Rail elaborated on this solution in supplementary written evidence:
Mr Hodgson [representing the PCA] agreed that Network Rail is not able to issue insurance backed guarantees due to the reasons outlined in point three of our original response to the committee. However, he did suggest that, were we to incorporate elements of the PCA’s best practice into our own guidelines for Japanese Knotweed treatment, the PCA would be able to officially approve our methods. In turn, this would enable our neighbours to obtain insurance backed guarantees, subject to PCA discussions with insurance providers.
Network Rail told us that it was currently updating its guidance “prior to submitting it to the PCA for review”. Network Rail was also looking at “opportunities to enrol Network Rail staff and contractors involved in the treatment of Japanese Knotweed onto training courses supported by the PCA”.
92.Network Rail had already indicated in oral evidence to us that it was open to considering using a mediation approach to address Japanese knotweed complaints:
We want our neighbours to feel that we do our best to work constructively and helpfully with them to tackle Japanese Knotweed and we try to always respond in a helpful, fair and consistent way to all complaints and claims. We’re absolutely open to mediation, where appropriate, as a positive way to settle a complaint and we will continue to avoid any kind of legal action, wherever possible.
Network Rail also set out that since 1 November 2005 it had spent “£454,351.42 in legal cases related to Japanese knotweed”. This figure related to 171 claims.
93.The challenge of resolving disputes relating to Japanese knotweed is diminished if a more measured and evidence-based approach is taken to Japanese knotweed. Nonetheless, we conclude that, in most if not all circumstances, where disputes between landowners relating to the encroachment of Japanese knotweed persist these are not usually best resolved by means of litigation, which can be both expensive and protracted. We recommend that, in consultation with the Civil Mediation Council, the Government produce additional guidance on dealing with such disputes, recommending that mediation via an accredited mediator be normally used, subject to the agreement of the parties involved, as the initial route to resolution of the dispute if it offers value for money, while explaining that this would not prevent an aggrieved party from having recourse to litigation if efforts to achieve a mediated settlement do not succeed.
94.We welcome the work that the Property Care Association and Network Rail have undertaken to identify solutions which enable Network Rail’s neighbours to obtain insurance backed guarantees relating to Japanese knotweed on Network Rail’s land. Network Rail’s revised guidance on this matter should be published no later than the end of 2019.
113 Anonymised response to the Committee’s call for personal stories relating to Japanese knotweed.
114 Environet UK Ltd ()
115 Advanced Invasives Limited () para 16
117 Environet UK Ltd ()
118 Home Office,
119 Chartered Institute of Ecology and Environmental Management ()
120 The Knotweed Company Ltd () para 3.1
121 Charles Lyndon Solicitors ()
122 Charles Lyndon Solicitors ()
123 Charles Lyndon Solicitors ()
127 Advanced Invasives Limited ()
128 The Guardian, , 3 July 2018
130 Charles Lyndon Solicitors ()
132 The Law Society ()
133 Charles Lyndon Solicitors ()
134 Network Rail ()
135 Network Rail ()
136 Network Rail ()
137 Property Care Association () and Network Rail ()
138 Network Rail ()
139 Network Rail ()
Published: 16 May 2019