A significant legal victory in a case brought by a householder affected by Japanese knotweed has established a right to recover a loss in value of your home from the stigma left by Japanese knotweed even after it has been treated.

Marc Davis purchased his house near Bridgend in South Wales in 2004 but did not realise that the plants growing on neighbouring council land were knotweed. In 2018 the local Council began tackling the plant with a “reasonable and effective treatment programme “

Mr Davies argued the presence of the plant -even once treated – had damaged the value of his house as it prevented him from landscaping, putting up a shed or building in the garden.

The Court of Appeal in the UK  agreed and awarded £4,900 in damages against the Council. In a judgment that his lawyer, Tom Carter, said established that one could recover damages for the stigma attached to the house, even after knotweed had been eradicated, and not just physical damage caused by it.

“Inevitably, if you’ve had knotweed and then had it treated, the rhizomes (roots) are still there in the ground, even though it’s been treated,” he said. “There’s then a stigma that’s attached [to the house].

“The importance of Davies is that it has confirmed beyond doubt that that loss [on the house value] can be recovered and that’s really the crucial issue.

“If the court of appeal had said no on that point, then anyone affected by knotweed could get the treatment costs but then they’d be left out of pocket for this loss of value of their home. And if they were to sell their home a year, five years later or whenever, they’d still suffer a loss at that point they wouldn’t have been able to recover.”

The principle that adjoining owners could be sued for encroachment of Japanese knotweed was established by the court of appeal in a 2018 case, brought by the owners of two adjoining bungalows in Maesteg, south Wales, against Network Rail.

Last month, a house seller was ordered to pay £32,000 in damages plus legal costs for misrepresenting to the buyer whether there was Japanese knotweed at the property. Surveyors have also been sued for professional negligence for failing to identify its presence.

This new Court of Appeal approach highlights what happens after the knotweed has been treated so it’s been found in the garden, hasn’t caused physical damage per se, but just having its presence because of the stigma attached … means somebody is going to pay less for this house than if the house had no knotweed at all.


If you have concerns about Japanese knotweed affecting your property, you can contact us for more information.