Japanese knotweed wipes thousands off home value as guidelines are ‘overly cautious’, say MPs

Japanese knotweed wipes thousands off the value of homes because Britain is ‘overly cautious’ about the menace, according to MPs.

The ‘seven-metre rule’, the danger zone from the invasive plant used to decide mortgages, is not now based on the latest scientific evidence.

MPs named lenders which refuse mortgages or make strict requirements if the weed is within that distance of a ‘habitable space’, which includes conservatories and garages.

Following a one-off inquiry, the science and technology committee said guidance should be updated this year.

It heard from one person who said Japanese knotweed had reduced their £340,000 house to a value of ‘zero’. But one expert claimed that ‘buddleia is actually ‘much more damaging and costly’. 

Committee chairman Norman Lamb said: ‘The UK’s current approach is more cautious than it needs to be. We need an evidence-based and nuanced approach.’

Japanese knotweed was introduced here in the 19th century and often requires heavy-duty weedkillers or excavations to get rid of.

But research suggests that damage to the one in 80 British homes it affects is ‘no greater than other disruptive plants’. The report describes the ‘seven-metre rule’ as a ‘blunt instrument’ as it rarely travels more than four metres.

The Law Society said it would consult to see ‘whether changes need to be made.’

HSBC, which was named as one of the reluctant lenders, said ‘we will consider all relevant guidance’.

Japanese knotweed was introduced here in the 19th century and often requires heavy-duty weedkillers or excavations to get rid of. But research suggests that damage to the one in 80 British homes it affects is ‘no greater than other disruptive plants’ [File photo]