Charles Lyndon is a law firm specialising in Japanese knotweed and the law. We have recently been successful on behalf of our client Mr Robin Waistell in a claim in private nuisance against Network Rail Infrastructure Ltd regarding Japanese knotweed. Once liability was established, the issue that remained was what the appropriate remedy would be.

The judge awarded Mr Waistell the cost of treatment and the residual impact upon the value of the property after treatment. The judgment established the principle that in cases of private nuisance private land-owners are entitled to the residual impact on the value to the property, owing to stigma in addition to the treatment costs.

In the case of Mr Waistell, the judge awarded Mr Waistell the cost of herbicide treatment. This was only because herbicide treatment was the only treatment proposed by the experts. However, in theory there is no reason why individuals should not be entitled to claim for the cost of excavation. In fact, there are a number of reasons why when claiming for the cost of treatment the correct measure should be the cost of excavation rather than the cost of herbicide treatment.

In private nuisance, a defendant has a complete defence to a claim if they abate or remove the nuisance. Herbicide treatment is not removing the nuisance, it is merely keeping it in check. Even if the herbicide treatment is successful in killing the Japanese knotweed, which we understand is not always the case, the affected soil on the claimant’s property is still classified as ‘controlled waste’ under the Environmental Protection Act 1990; and the claimant will still have to declare that the property is affected by Japanese Knotweed if he or she wishes to sell at some point in the future.

This is not just the case in private nuisance, but it is arguably true for cases involving misrepresentation and professional negligence. For instance, in cases of misrepresentation where the seller of a property has made a false statement on the Property Information Form (TA6) by stating that the property is not affected by Japanese knotweed, a buyer is entitled to a measure of damages that would put him or her in the position they would have been had the statement been correct. Many sellers argue that the buyer in these circumstances should only be entitled to the cost of herbicide treatment, but we do not believe that this is correct because the representation that the seller made was that the property was not affected by Japanese knotweed, not that the property was affected albeit that there was a herbicide treatment programme in place. A buyer should therefore be entitled to the cost of excavation plus any residual impact on the value of the property.

A similar logic applies in cases of professional negligence where a surveyor has failed to notice and report on Japanese knotweed. In this scenario, the surveyor has inspected the property and informed the buyer, either explicitly or implicitly, that the property is free from Japanese Knotweed. Again, in order to put the buyer in the position that they would have been in had the surveyor performed the contract correctly and not been negligent, the property has to be free from Japanese Knotweed and the only way to properly achieve this is to excavate it.

Although we understand why many eradication companies prefer herbicide treatment, as a course of action from a legal perspective, excavation better achieves the position of placing an individual in the position he or she should have been in but for the defendant’s fault.

Dorothea Antzoulatos & Mahsa Tavakol, Charles Lyndon