Knotweed already marching apace into one of the fields(presently under crop) next to the site at Standish Hospital.
Note that the field margin alone is no longer adequate in preventing many forms of the mechanical disturbance necessary for further spread.
Strimming, mowing or cutting is an efficient means of ensuring the knotweed's propogation, as viable plant material gets ejected offsite. In a regularly-ploughed and fertile field, the ease and rapidity of further spread can only be imagined via a combination of overground mechanical means(farm machinery and tyres)and underground habit.