Environmentalists claim there is no scientific justification for further GM crop trials at an Oxfordshire farm.

Oxfordshire Friends of the Earth said a fourth series of spring trials on farmland near Faringdon goes against the views of scientists conducting experimental planting of genetically modified maize and oilseed rape.

Farmer Christopher Lewis angered residents and campaigners by allowing three test crops to be grown last year at Glebe Farm, near Hinton Waldrist and Longworth.

Two weeks ago, when the Government announced the farm would be included in further spring trials, Mr Lewis said his views on genetic experimentation had not changed.

Mr Lewis, who has farmed the land since 1959, said: "We've all got to accept that the world's population is going to increase dramatically and that food production has to increase accordingly.

""There are 155 million acres of GM crops growing worldwide, which is 10 times the cultivated space of this country. Worldwide there is not one recorded case of anyone who has suffered from a GM crop."

But Jean Saunders, Oxfordshire FoE spokeswoman, said the fact that Glebe Farm had again been chosen for GM tests proved the biotech industry had failed dismally to find farmers willing to take part in fresh trials.

She said a recent Farm Scale Evaluation interim report had expressed concern that the study may become too dependent upon a relatively small base of farmers., perhaps reducing the range of variation of farm management included within the study."