. Now Environet, an invasive plant specialist which excavates and removes knotweed infestations, has

Japanese knotweed costs Britain ￡41 million a year, a study has found, as experts call for more investment to stop future invasive species reaching the UK. The nightmarish plant was introduced to the UK more than 150 years ago and is notorious for its ability to cause significant structural damage and being extremely difficult to kill.Dr Ross Cuthbert of Queen’s University Belfast led a project to analyse the economic impact of all the UK’s invasive species, and found that since 1975, they have