Japanese Knotweed : Davies v Bridgend County Borough Council Revisited

Six months after the Supreme Court ruling in Davies v Bridgend County Borough Council on Japanese Knotweed (JKW), the decision has clarified landowner responsibilities and reduced liability risks tied to this troublesome plant. Here’s what you need to know.

The Case Summary

• Claimant’s Allegation: Mr. Davies accused Bridgend Council of negligence for failing to control knotweed near his property, claiming "stigma" damages due to devaluation caused by the plant’s prior presence.
• Court of Appeal: Initially supported Mr. Davies, ruling the council’s breach of duty during infestation made them liable for property value loss—even if the knotweed’s presence didn’t directly result from their negligence.
• Supreme Court Decision: Overturned this, reaffirming a key legal principle of "but for" causation. Damages are only recoverable when the defendant’s actions directly cause new losses. Since Mr. Davies’ property stigma arose from the initial infestation, the council’s later actions didn’t increase his losses.

Implications for Homebuyers and Landowners

1. Reduced Liability for Landowners: Historic knotweed infestations are less likely to result in claims, provided current inspection and treatment practices comply with standards (e.g., RICS and PCA guidelines).
2. Decline in Viable Claims: Cases for stigma-related property losses are dropping, with many claims dismissed or discontinued.
3. Evolving Knotweed Risks: The stigma around knotweed is less severe, thanks to increased awareness and management strategies.

What Homebuyers Should Do

• Get a Professional Survey: Ensure any property inspection checks for JKW to identify risks early.
• Act Promptly: If knotweed is present, arrange for professional treatment to prevent spread and reduce liabilities.
• Stay Proactive: The case highlights the importance of proper management. A well-executed treatment plan can protect property value and minimise future disputes.

The ruling reassures landowners and buyers that knotweed isn’t the dire threat it once was—but vigilance and responsible care remain essential.