Between 500 and 1,000 horses die each year after eating ragwort, a poisonous yellow weed which is common throughout the countryside of Britain.

Ragwort poisoning causes slow and certain destruction of the liver. It probably causes more loss to the UK livestock industry than all the other poisonous plants put together.

Death follows symptoms

Symptoms do not show until the later stages of poisoning, when death is inevitable.

The Politics Show examines John Greenway's attempts to cut the death toll.

Private member's bill

John Greenway MP represents the rural North Yorkshire constituency of Ryedale, where a number of top racing stables are based.

Mr Greenway is due to introduce a Private Member's Bill into Parliament in late March, called the Equine Welfare (Ragwort Control) Bill.

Councils would be responsible

This would give public landowners the legal duty of controlling ragwort effectively and preventing it spreading onto land where horses, ponies and donkeys graze.

Factbox

Ragwort seeds can lie dormant for 20 years Each plant produces 250,000 seeds Very poisonous, horses and cattle are most at risk A horse can get ragwort poisoning by inhaling or eating wind-blown seeds In Tasmania, biological control led to the destruction of 85% of the plants Wear gloves, the poison can penetrate the skin.

Mr Greenway has drawn up the measure in partnership with the British Horse Society. He says the Bill is also supported by the British Horseracing Board and the National Farmers Union.

But not everyone is in favour. Some councils say if the Bill becomes law they could end up having to spend large amounts of money on ragwort clearance.

Environmental issue

Wildlife campaigners claim that some species of insect, which eat ragwort, could be threatened if too much is cleared.

They are particularly concerned about the cinnabar moth, whose caterpillars feed exclusively on ragwort.

Have your say

Do you live close to ragwort infested land? How can the problem be solved? Let us know by filling in the response form below.

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