Homeowners in Slough are being warned to be vigilant after 26 infestations of Japanese knotweed were found within 4km of the town.

The Environment Agency describes the horticultural invader as “indisputably the UK’s most aggressive, destructive and invasive plant”.

But new figures by YouGov have found the weed is no longer the deal-breaker it once was for house buyers, with a reported 32 per cent of people who are aware of the plant saying they would still buy an affected property but expect to pay less.

The research, which was commissioned by Environet UK, found 78 per cent of British adults are now aware of Japanese knotweed compared to 76 per cent in 2018 and 75 per cent in 2017.

While half (50 per cent) of those who are aware of the plant said they would walk away from a property which had Japanese knotweed, this is significantly less than the 78 per cent who stated they would not buy an affected property two years ago, suggesting people are becoming “increasingly pragmatic” in their approach to the UK’s most invasive plant.

Of those who said they would go ahead with the purchase at a reduced price, 26 per cent would expect a discount of between six and 10 per cent, while 15 per cent would expect to knock off between just one and five per cent. A further 15 per cent would want to reduce the price by more than a quarter.

Nic Seal, founder and MD of Environet said: “With an estimated five per cent of all UK properties now affected by Japanese knotweed, either directly or indirectly, it’s encouraging to see homebuyers becoming increasingly rational in their approach.

“If left untreated, Japanese knotweed can cause considerable damage to a property which is why buyers and lenders are right to insist that there is a professional treatment plan in place before they agree to proceed.

“Due to the stigma around Japanese knotweed, the property value will almost certainly be impacted, but all that’s required is a sensible renegotiation of the price. People are realising it doesn’t have to be a deal breaker.”

Chartered surveyor Paul Raine, director of Expert Surveyors Ltd, added: “The key to selling a property affected by knotweed is a Japanese Knotweed Management Plan from a reputable specialist.

“Always be honest if the property you’re selling is or has been affected, or it could come back to bite you in the form of litigation from your buyer further down the line.”

Environet estimates between 850,000 to 900,000 UK households are affected by the weed, suffering an average reduction in value of around 10 per cent and knocking almost £20 billion off property values.