Environmentalists have rejected a government plea for debate on GM crops, claiming it is time for a ban not dialogue.

The snub from the powerful green lobby follows Margaret Beckett's launch of an "open and balanced" discussion on the controversial bio-technology.

"The government wants a genuinely open and balanced discussion on GM. There is clearly a wide range of views on this issue and we want to ensure all voices are heard," she said on Friday.

Friends of the Earth - the group that branded crop science "Frankenfood" - argue that the public's mind is made up.

FOE's, Adrian Bebb, says GM crops should not be commercially grown in the UK. "People have already rejected GM food. That is why food companies have all gone GM-free," he said.

"We don't need discussion, we need action. The government must start listening."

The environmentalists believe biotech crops will "contaminate" existing agriculture.

"If GM crops were commercially grown in the UK it would lead to widespread GM contamination of conventional and organic crops, honey and plants in the wider environment," claims Bebb.

"Why risk this when there is clearly no market for GM food in the UK?''The environment secretary wants a discussion to start in autumn. She shares the view of the Agriculture and Environment Biotechnology Commission that public debate will help deepen public understanding of GM.

"If there are gaps and uncertainties in knowledge these need to be ascertained, acknowledged and addressed," Beckett said.

"The government wants to provide people with the opportunity to debate the issues openly and reach their own judgments.''