Three members of the GenetiX Snowball group uprooted 10 sugar beet plants at Sharpe's Seeds Ltd in the village of Boothby Graffoe, near Lincoln, said a police spokesman.

Eight other members were found nearby and arrested for alleged criminal damage.

Soya beans: One of the most widely available GM foods

The nine men and two women were part of a group of 30 environmentalists who had been protesting against genetically altering food.

Andrew Wood, spokesman for GenetiX Snowball, said the group believed that genetically engineering plants to make them more resistant to insects or disease was "unnecessary and unwanted".

He said that they wanted a five-year moratorium on GM technology in line with a recent poll which had suggested that three-quarters of people wanted the crops banned.

He added: "There are important environmental concerns - herbicides create a scorched earth area, damaging wildlife. Genes can also cross species, creating superweeds.

"Also, we don't know about the long-term health effects. GM crops are totally unnecessary."

Prince Charles: Spoken out against GM crops

Genetically modified crops have been at the centre of a growing debate over the powers of the science.

The Prince of Wales has described genetically altering food as taking "mankind into realms that belong to God, and to God alone"

Organic farmers fear that cross-pollination from genetically altered crops will destroy their own produce but companies researching the technology say that the principles involved are no different from what farmers have done for thousands of years.