Another tricky point: knotweed has often been condemned for its old woody growth harbouring vermin. Certainly this is true...and this may be a further problem particularly in urban sites. In more rural areas(like this one) it will provide protection and cover to wildlife. Given that knotweed here is well-established on onsite tipping or waste areas and that disturbance of the site by wildlife is frequent, care will need to be taken in compiling a cogent eradication plan.