Reducing some of the most deadly environmental poisons to safe levels for children could take at least 20 years, a Government report reveals.

Eradicating dioxins - linked to cancers, infertility and poor brain development - from the UK could cost industry a staggering £10 billion.

A consultation document for Ministers says that lowering the dietary intake of dioxins for toddlers below tolerable levels is unlikely to happen for the 'foreseeable future'.

Dioxins are produced by industrial processes such as electricity generation at power stations and the incineration of household waste. Quantities have also been detected in fish. Risks to health come from long-term exposure at high levels.

Mike Childs, toxins campaigner for Friends of the Earth, said: 'Dioxins are among the most toxic chemicals. We need to get rid of them as far as possible to protect the most vulnerable members of society such as children. Although it will cost billions, it is a price worth paying.'

Dr Andrew Sherwood, research fellow at the Institute of Environmental and Biological Sciences at Lancaster University, who helped compile the report, said new research was required to quantify the risk. 'The question is whether a very low level long-term dose is causing any health problems.'

The Food Standards Agency has already warned consumers not to eat too much fish because of their dioxin content.