Ragwort is mentioned in the Weeds Act 1959. This is what the Act says
"(1) Where the minister of Agriculture fish and food (in this act referred to as ' the Minister') is satisfied that there are injurious weeds to which this act applies growing upon any land he may serve upon the occupier of the land a notice, to take such action as may be necessary to prevent the weeds from spreading.
(2)This act applies to the following injurious weeds, that is to say-
creeping or field thistle
broad leaved dock
It is a piece of legislation that provides for AN ORDER to be made. There is nothing that says that you automatically MUST eliminate this plant from land. It is similar to legislation creates orders for traffic such as yellow lines. It is not automatic but only happens where there is problem.
It is commonly claimed that this legislation forces landowners to control ragwort or that it places an obligation on them to do so. As can clearly be seen from the actual contents and text of the act this is not the case. It is not unknown for even such august bodies as local councils to get this matter wrong. This is the text of the act and this is what it says. The rest of this rather short act of parliament is about procedure and powers but has no bearing on the obligations and requirements placed on landowners in general. For completeness a copy is available here. The Weeds Act 1959
The Weeds Act has been subsequently amended by the Ragwort Control Act 2003. but this has no real effect on the information given on this page.
There is also another myth that ragwort is a "Notifiable Weed" that must be reported to someone. Since this is the only piece of legislation that can place an obligation on anyone and it does not say that it is notifiable this is clearly a myth. There is no requirement in law to nofify, inform or tell anyone of the occurence of ragwort anywhere. See Notifiable weed