There has been no formal assessment of this nature. Japanese knotweed is listed on Schedule 9 of the Wildlife and Countryside Act 1981 (as amended), which makes it an offence to allow the plant to escape, or cause it to grow in the wild. Local councils and police have the power to issue Community Protection Notices against individuals or businesses who persistently or continually act in a way that has a detrimental effect on the quality of life of those in the locality.
A number of authorities are taking action to control Japanese Knotweed. This includes the Tees River Trust which is involved in managing release sites for the biocontrol of Japanese knotweed.