It isn't just house buyers who need to be cautious, either. Since 2013, anyone selling a property has been required to check their garden for Japanese knotweed and declare its presence on the TA6 Property Information form. Sellers “must now be certain there is no knotweed present, including rhizome beneath the ground or within three metres of the boundary, even if there are no visible signs above ground”, explains OnTheMarket.

Sellers who aren't aware of any infestation are still advised to respond “Not known” to the Japanese knotweed question on the TA6 form, leaving the buyer to "undertake their own enquiries." If knotweed is present, the property may be harder to sell, but not impossible.

In 2018, a homeowner in Streatham, London, was sued for £32,000, for not declaring that his property contained Japanese knotweed, before selling it. You have been warned!

UK's worst Japanese knotweed hotspots revealed