On the 12th August 2004 the Oxford Mail printed a letter from Dinah Harris county welfare officer of the British Horse Society, which was full of inaccuracies. Here are the salient excerpts.

Sir, As county welfare officer of the British Horse Society and in the interests of public safety I am replying to John Macallister's letter ( Oxford Mail August 4) to correct some of the misleading statements about common ragwort.

This is typical of the hysterical tone of the letter as the public safety aspects of ragwort are negligible and ironically Harris's letter is grossly misleading in itself.

"Acts of Parliament outlaw ragwort due to its poisonous nature and the severe environmental and economical[sic] damage caused by the spread of this dangerous weed."

Ragwort is most emphatically not outlawed by acts of Parliament. See Ragwort law
It is a myth that was repeated in a number of adverts including a joint British Horse Society leaflet which were stopped after action by the Advertising Standards Authority. It was repeated in a slightly different form in the society's Ragwort Toolkit.

"The toxins in ragwort are called pyrrolizidine alkaloids (PAs) these can cause death when eaten by cattle,sheep,pigs,goats and dogs."

This is exaggeration as deaths are actually very rare and are caused by some form of animal abuse. There is a page on Ragwort and dogs on this site. A subsequent letter replying to this one quite properly ridiculed the threat to dogs.

"The reason for clearing roadside verges and commons is threefold. To comply with the law."

As stated above there is no automatic legal requirement to control ragwort so there is no such reason.

"Secondly when left uncontrolled , ragwort will spread at an alarming rate, providing up to 156,000 seeds per plant , with 80 per cent of these germinating. This will produce dense areas of ragwort that will smother our small rare wild plants."

This is just nonsense. The seed numbers figure is a highly exceptional one and a similar figure used as an absolute was also banned by the Advertising Standards Agency. The actual surveyed figures from material published in scientific journals show it is usually lower and they can be found here. Ragwort seed production.
Eighty percent of the seeds are not going to germinate under natural conditions and if they do they are not going to grow into plants. In fact many of them remain on the parent plant. If these figures were to be taken literally we would have all been buried under the weight of ragwort plants many years ago.

On average one plant produces one new plant each generation. In fact during this time it would have been slightly lower than this because a government survey showed that ragwort was declining. This is a normal figure for many plant species. It says little about reality, being a laboratory figure not that observed in nature and is misleading as a result.
See Ragwort seed germination

Thirdly the ragwort seeds are wind dispersed and, according to research, will spread up to 10 miles.

This is hysterical hyperbole. The seeds do not have any motive force and have parachutes not wings. Normally in nature the research shows that the seeds in fact only travel for a few metres see Ragwort dispersal

The same error was made in Parliament by Baroness Masham a vice president of the British Horse Society. To be clear this is hysteria because it exaggerates the wind dispersal. Yes it is possible for seeds to travel long distances, but in the context of what we know 10 miles is hyperbole. In fact you could never measure this properly in the UK because there is nowhere that is likely to be 10 miles from a ragwort plant.