But police arrived before they completed their task and arrested three people following brief scuffles.

The protesters left the scene around an hour afterwards in order to find where the three were being held and handed to authorities a list of all protestors in what they described as a gesture of solidarity.

The protestors "are ready to assume responsibility for their actions, including in court and including in the face of proceedings which could be serious," Bove told reporters. "I act with my face uncovered, I take responsibility for my actions."

Bove, a leading figure within the anti-globalisation movement who in the past has been imprisoned for similar actions, said the crops were indeed genetically modified.

"We covered more than 400 hectares (990 acres) across the whole of the southwest to determine whether they were GM. Here, we were able to verify it," he said.

He added that organic farmers in the area had uncovered evidence of "genetic pollution" and a "risk of contamination" up to several hundred metres (yards) from the field.

Greenpeace militants had also targeted the same field in July, marking a cross in the centre of a 30-metre (100-feet) circle, leading to the arrest of six activists from the ecological organisation, who were subsequently released.

The farmer concerned, Claude Menara, sued Greenpeace and forced it in the same month to remove from its website a map showing GM maize fields.

Bove came to international fame in 1999 when he was one of a group who demolished a half-built McDonald's eatery in the southern town of Millau.

Recently he has let it be known he is considering running for the French presidency in 2007.

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