Posted: 19/06/2015 at 12:53
I beleive animal husbandry legislation requires owners of livestock to ensure that there hazards of which ragwort could be considered one are controlled on their own land, but there is nothing to require neighbouring landowners to control it, although it is generally accepted that it is good practise to.
Having pulled ragwort as part of a summer job (used to use some land adjacent to a stables and it was part of the agreement they hadwith my employer) personally I pull any I see in the garden.
Need to be a bit careful pulling ragwort in the wild as some species are protected.
Looking up Hostafans suggestion - you might not want it as a plant even though it's not ragwort: