Plants containing the deadly poison ricin are being used in council-maintained ornamental gardens across Keighley and Silsden.

Castor Oil plants -- or ricinus communis -- are being used in displays across the district, sparking concern among parents.

The Bradford Council flower beds feature the striking shrubs, whose seeds contain a water soluble form of ricin.

A concerned woman from Silsden contacted the Keighley News on spotting ten Castor Oil plants growing in the small raised garden by the car park in Briggate, where children and youths gather.

The castor beans are highly toxic and death is likely with the consumption of even a small amount.

The woman urged parents to warn their children about the dangers of the plant as there have been fatalities following accidental consumption of the seeds.

It is recommended by horticultural experts that Castor Oil plants in a garden should not be allowed to flower and seed. Gardeners are encouraged to snip off the flower heads before they develop into seeds.

A spokesman for Bradford Council -- alerted to the dangers by the Keighley News -- said it aimed to deadhead all the existing plants to remove the seeds and a risk assessment would be conducted.

If the castor beans are ingested, the toxin can cause stomach irritation, diarrhoea, abdominal pain, increased heart rate, profuse sweating, collapse, convulsions and death.

The plants are stout, robust and shrub-like, with reddish stems and greenish-white or reddish-brown flowers produced in narrow, upright clusters.

The fruit is a three-lobed, green or red capsule with a soft, spiny exterior, containing three oval brown seeds on average.

The seed is only toxic if the outer shell is broken or chewed open.

The Department for Health warned that if a child consumed between one and three seeds they could die, and that if an adult ingested about eight, death would be likely.

Signs of toxicity may not manifest for 18 to 24 hours after ingestion, with death generally occurring within 36 hours of consumption.

Commercially prepared castor oil contains none of the toxin. Ricin is considered a chemical and biological weapon and is explicitly prohibited.

A Bradford Council Parks and Landscapes spokesman said: "Castor Oil plants are widely used as part of annual bedding displays. We have used them in the Bradford district for many years.

"We have about 50 plants this year on display, but will be carrying out a risk assessment before we use them next year."

There is no known antidote to ricin poisoning. Per gram, it is 6,000 times more poisonous than cyanide.

The most infamous case of ricin poisoning took place in 1978, when the KGB was suspected of stabbing Bulgarian dissident Georgi Markov with an umbrella on London's Waterloo Bridge.

The umbrella was loaded with a special pellet containing a fatal dose of ricin.

Twenty-five years later, ricin re-appeared in London, when a quantity of the poison was found in the possession of North African-born Al Qaeda suspects. Many other garden plants are also highly toxic, including rhubarb leaves, autumn crocuses, delphiniums, foxgloves and laburnum.