What was the case about?

The case involved a dispute between the owners of two adjoining pieces of land in Wales. One, owned by the Council, had Japanese knotweed – an invasive plant found in the UK – on it for some time. Mr Davies then bought the land next door as an investment. 

The Council treated the Japanese knotweed, but Mr Davies claimed that the value of his property had nonetheless deteriorated because of the ongoing “blight” of knotweed, which can damage concrete foundations and other building structures. While the knotweed itself had been treated, the roots remained and could cause further damage, which meant there was a stigma attached to his property, affecting its value. 

The County Court decided that Mr Davies’ claim was not for the damage caused by the knotweed but for “pure economic loss”, and as such could not succeed as a matter of English law.

Court of Appeal decision

Mr Davies appealed. Although the loss he claimed was small (under £5,000) the Court of Appeal considered that there was a sufficiently important point of principle for them to hear the case.

The Court of appeal was clear that the mere presence of knotweed could constitute an actionable nuisance as long as it was “not trivial”, with no need to show that it caused a risk of damage to structures on neighbouring land, or increased difficulty in developing the land.

The Court of Appeal allowed Mr Davies’ appeal and said that physical encroachment of knotweed onto his land would affect his use and quiet enjoyment of it, and amounted to “damage” to the property, causing a nuisance. Because the nuisance arose from damage to the property, a claim for diminution in the value of land wasn’t a claim for “pure economic loss”, it was for consequential loss arising from that damage.

It did not matter that the knotweed on the Council's land was historic and predated Mr Davies’ ownership – the persisting encroachment onto Mr Davies’ land was a continuing nuisance, giving rise to a claim.

What next?

The Court of Appeal was aware that this would be a significant decision due to the high volume of knotweed cases going through the UK court system, hence their willingness to consider it despite the small amount involved.

This will be welcome news for those who unwittingly purchase property affected by knotweed on neighbouring land, and could potentially open the flood gates to many more claims.

It will be less welcome news for those with knotweed on their lands, who could face claims from their neighbours long after they thought that they had eradicated the problem.

It also leaves the door open for nuisance claims for other environmental contaminants which, although they have been remedied, may still be seen as a "blight" on neighbouring land

Authored by Mathew Ditchburn and Lucy Redman.