By Environment Correspondent Alex Kirby

Friends of the Earth (FoE) has written to 20 farmers in England and Scotland, urging them to abandon trials of genetically-modified (GM) crops, which it says are illegal.

The farmers are growing winter oilseed at 24 sites from Hampshire to Aberdeenshire - three farm-scale trials, 11 trials for seed listing, and 10 research and development sites owned by the biotechnology company AgrEvo. All the sites are covered by what is called a government "release consent".

But FoE has told the farmers the trials are illegal because a court ruled last month that the permission given by the government for the crops to be planted was itself illegal.

The Cabinet Office GM communications unit told BBC News Online the trials were vital, and that FoE had not asked the court to rule on whether they could go ahead.

Technical issues

Last August, FoE challenged a government decision to vary a GM release consent it had issued to AgrEvo. In September, the government and the company conceded that the variation had been unlawful, and agreed not to contest FoE's case.

The Environment Minister, Michael Meacher, said then that the decision not to contest the FoE challenge had been made on technical grounds, not from any fears over the trials' safety.

And he said he thought the present trials should be allowed to go ahead.

On 24 November, the High Court formally ruled that the consent variation had been unlawful, and ordered it to be quashed.

In a letter to the farmers, FoE says it "believes that these GM winter rape crops should not be in the ground and should not remain there".

"We respectfully urge you, as strongly as we can, to consider destroying them."

FoE suggests that the farmers might prefer to consult their own lawyers "rather than taking advice directly from AgrEvo or the government, who have their own interests to protect".

In another letter, to Mr Meacher, FoE urges him to order the crops' destruction, as the legal conditions which applied to the original release consent are no longer valid.

Legal successes

The group has twice before succeeded in establishing the illegality of government action over GM crops.

In July 1998, it won a Court of Appeal ruling that the government had been operating the Seed Regulations illegally, thus allowing GM seeds to avoid two years of testing and move more quickly towards commercial approval.

In March this year, the Provisional Seed Certification Scheme, which was another way of allowing GM seeds to save two years on their way to market approval, was admitted by the government to be unlawful.

The admission came in response to a legal challenge by FoE and three MPs. Liana Stupples of FoE said allowing the oilseed crops to stay in the ground "would simply bring the law into disrepute".

"Public confidence in GM crops is already at an all-time low - allowing these crops to continue to grow will only let it sink even lower."

The Cabinet Office GM communications unit told BBC News Online that the trials were vital, and that FoE had not asked the court to rule on whether they could go ahead.