The Royal Horticultural Society gets it wrong.

The Royal Horticultural Society has also succumbed to the misinformation about ragwort.
This is a statement on its website.

The Weeds Act specifies five injurious weeds: common ragwort, spear thistle, creeping or field thistle, broad-leaved dock and curled dock. The Ragwort Control Act 2003 (which amends the Weeds Act 1959), imposes a duty of responsibility on landowners to effectively control Senecio jacobaea, preventing its spread onto grazing land.

This is wrong.

The Ragwort Control Act imposes no duties on anyone. It merely says

(1) The Minister may make a code of practice for the purpose of providing guidance on how to prevent the spread of ragwort (senecio jacobaea L.).

Of course the problem is there have been people going around campaigning against this ecologically valuable weed which has then led to trouble. Like the problems in the British Horse Society / Advertising Standards Authority affair.

Oh and in case anyone is wondering the Weeds Act doesn't impose any automatic duty on anyone to get rid of ragwort either!