In case the last post by Steve Barron gets removed, with the very useful link to a company that removes Knotweed, I have made a note of address and can pass it on to anybody who wants it - not that I can recommend them personally.

I was really worried when I went to Dulwich Woods this weekend and saw a huge amount of knotweed just beyond the limits of the woodland. If knotweed got into the woods it could be devastating.