A NOTORIOUS poison has been gracing flower tubs in a Dorset town this summer... and they've inadvertently helped Wimborne scoop a couple of top trophies.

Wimborne in Bloom organisers have only just discovered some of the plants that helped them triumph over rivals this summer harbour deadly ricin - more often associated with Osama bin Laden than the peace-loving burghers of the Minster town.

Wimborne in Bloom won a silver-gilt medal in Britain in Bloom and a gold medal and champion of champions for the south and south east of England.

But a committee member of Wimborne in Bloom cut down all the offending plants from their tubs after a complaint.

The attractive castor bean is the source of ricin which is 6,000 times more poisonous than cyanide.

Georgi Markov, the Bulgarian dissident, died when his murderer stabbed him with a ricin-tipped umbrella at a London bus stop in 1978.

And stockpiles of the chemical were found in caves associated with al-Qaeda following the invasion of Afghanistan.

Wimborne in Bloom secretary Christine Oliver said the castor beans were planted "in all innocence".

"The people that actually planted the tub put them in," she said.

"People said how lovely they are. Lots of parks and gardens grow them. They are not considered unsafe by the nursery and certainly the judges never mentioned it.

"Somebody contacted the town hall and the message got through to the rest of the committee.

"Val Baker took them out for safety.

"We would not have known there was anything wrong with them till somebody complained."

Two of the plants grew outside Mrs Oliver's own home in Park Lane, one at Pye Corner and one outside a furniture store in East Street.

"Eighty per cent of plants are poisonous if you start putting them in your mouth," Mrs Oliver added.

According to a Channel 4 website ricin is one of the most deadly of naturally-occurring poisons. One milligram could kill an 11-stone man. The castor bean plant is a native of tropical Africa where it can reach a height of 15ft, according to horticultural websites. Sometimes its dried seeds are sold to tourists as necklaces. It is poisonous to people, animals and insects. Symptoms in humans include abdominal pain, vomiting and bloody diarrhoea followed by severe dehydration, drop in blood pressure and death.