Selling a House with Knotweed: How to Answer TA6 Question 7.8 Legally

Authored by Property Care Association Specialists • Updated October 2026

When selling residential property in England and Wales, the seller is legally required to complete the Law Society Property Information Form (TA6). Question 7.8 deals specifically with Japanese knotweed: "Is the property affected by Japanese knotweed?" The form offers three possible answers: Yes, No, or Not known. Choosing the wrong answer carries severe financial consequences.

1. The High Risk of Answering "No"

In conveyancing law, ticking "No" is an affirmative declaration that you have inspected the property and are confident Japanese knotweed is not present within the boundaries or on adjoining land within 3 metres. If a buyer discovers live rhizomes or dead canes after moving in, they can sue the seller for fraudulent or negligent misrepresentation.

In high-profile landmark cases such as Henderson v Small (2023), the Central London County Court awarded a home purchaser over £200,000 in damages and legal costs after a seller falsely claimed knotweed was not present. Even if the weed was cut down or covered with bark chips, forensic botanical testing can prove whether rhizome networks existed prior to the sale.

2. When to Answer "Not Known" vs "Yes"

If you have never seen knotweed on your land and have no specialist knowledge, solicitors recommend selecting "Not known". However, if you are aware of past or present knotweed, you must tick "Yes" and provide:

• A detailed Knotweed Management Plan (KMP) produced by an accredited Property Care Association (PCA) contractor.
• A valid, transferable 5 or 10-year Insurance-Backed Guarantee (IBG).
• Receipts and chemical treatment logs demonstrating ongoing professional management.

3. How a 10-Year Guarantee Saves Your Property Sale

Declaring knotweed on the TA6 form does not kill your house sale if properly managed. In fact, providing a certified PCA management plan and an insurance guarantee satisfies the underwriting guidelines of major UK lenders (Halifax, Nationwide, Barclays). The lender will proceed with mortgage release, and the buyer will have peace of mind that their asset is protected.