The idea is part of British Nuclear Fuels Ltd's (BNFL) latest move against radioactive contamination.

It hopes that the sunflowers, planted earlier this year in a lightly polluted trench at the ageing Bradwell Power Station in Essex, will have sucked up the contamination.

BNFL says the plants can then be burnt safely.

'Early days'

The aim is to prevent hundreds of tons of soil having to be dug up and taken to its radioactive waste store at Drigg in Cumbria.

Technicians also planted spinach, Indian mustard and sugar beet in the trench.

BNFL spokesman Robin Thornton said the amount of radioactivity involved was very small.

"If we can get the plants to draw out the radioactivity and clean the soil all we would have to do is burn the plants and dispose of the ash," he said.

"It is early days yet but if we find the right plants and best methods it would apply to different types of toxic materials and clean up other contaminated sites."

Scientists will test the harvested plants to see which variety is most successful in collecting radioactivity.