Japanese Knotweed

First day back in work today after a 12 day break; to make matters worse I had to visit the dentist for a check up first. I need a filling but I have to wait a month until I can get to see the dentist again. They are getting as bad as Doctors surgeries now.

Anyway this Japanese Knotweed is growing through the tarmac at our rear car park in work. How strong is this weed!!!