A concerned member of the British Horse Society (BHS) has brought to our attention the letter from Brian Knight, entitled “Ragwort facts” (Letters, August 9). The BHS is concerned by some of the statements in Mr Knight’s letter and would like to clarify the current position.

Presently, the BHS is having to deal with high volumes of calls from concerned members of the public reporting horses and ponies grazing in fields full of ragwort and ragwort on adjacent land to horse paddocks.

Ragwort has been a cause for concern for a number of years but with the exceptionally wet summer last year, ragwort is growing in abundance across Britain.

The BHS campaigns against the spread of ragwort because of the fatal effect it can have on horses over a period of time. However, the BHS is aware of the conservation issues regarding this plant and the British Horse Society Scotland, Plantlife Scotland and Butterfly Conservation Scotland joined forces to launch a new guidance leaflet on ragwort which aims to build a consensus around the management of this contentious flower.

Horses only require continuous ingestion of small amounts of this plants over a period of time for irreversible liver damage to occur.

The clinical signs of ragwort poisoning can be distressing with no treatment available once liver failure has occurred. Different individuals appear to have different susceptibilities to the toxin but the BHS would be cautious of the statement given in the letter that a horse would have to eat between five and 25 percent of its own body weight of ragwort to be poisoned.

There is a responsibility for the landowners and relevant authorities to ensure ragwort is cleared as appropriate.

The Weeds Act 1959 allows the Secretary of State for Environment, Food and Rural Affairs to take statutory action to control the spread of a number of weeds, including ragwort.

As with all enforcement authorities, in this case Defra, resources can be an issue, but this should not be an excuse not to clear ragwort as appropriate.

Emmeline Hannelly, Welfare Executive, The British Horse Society, Kenilworth