Environment correspondent Robert Pigott: "Banning the crops could alienate the EU"

Environmental groups and the government's wildlife adviser English Nature have repeated their call for a moratorium preventing farmers from having access to the controversial new agricultural technology until 2002 at the earliest.

One pressure group predicted genetically modified (GM) crops could lead to "chemical and genetic" warfare across the UK.

Reacting to fears, Environment Minister Michael Meacher said the government could impose a moratorium if experts proved a potential risk to public health and the environment.

Fears: Campaigners say GM crops gone far enough

No GM crops have been cleared for commercial cultivation in the UK, but they are being widely tested on specially licensed sites. Environmentalists argue a moratorium would allow for extensive research.

The crops are created by splicing genetic material from other species into the crop's DNA.

The foreign genes are chosen to make crops resistant to specially developed pesticides, which kill everything else.

Michael Meacher: "Careful consideration"

The government says there is no firm evidence to back claims that GM produce could be harmful - but it is compulsory to label all food containing them.

English Nature and environmental groups are also worried that GM crops could breed with wild plants, reducing the population of insects and birds.

Tony Juniper, of Friends of the Earth, told Radio 4's Today programme: "I do not believe that the implications of these crops in ecological terms has been properly explored.

Producers: Argue GM crops benefit environment

"For example, there could be very serious implications in farm and wildlife arising from the use of crops which are tolerant to broad spectrum pesticides."

If the resistant gene was bred into harmful weeds, he said, there could be "chemical and genetic warfare".

And he added that GM crop producers were merely conspiring to hold the monopoly in both seeds and pesticides.

Tony Juniper: "Serious impact on farm and wildlife"

Roger Turner, chairman of the group representing GM crop producers, conceded that the genes "probably would" cross to other species.

But he insisted that the crops would be beneficial to the environment.

"You are no longer dependant on having multiple applications of cocktails of chemicals to remove the weeds."

Europe: Opposes moratorium

He said that the use of just one pesticide at specific times would allow wildlife supported by the crop to live longer.

Environment minister Michael Meacher said: "A moratorium certainly has to be justified as necessary to protect public health or the environment, or both.

"And the evidence for it has to be clear and sufficient.

Roger Turner: "No longer dependant on cocktails of chemicals"

"We are now examining the whole issue extremely carefully."

Ministers have consulted environmental organisations and seed companies during the past week to see whether a voluntary practice can be agreed, Mr Meacher said.

Europe

But banning the crops could alienate the EU which largely controls how new crops are developed.

Dr Patrick Dickson: "The British government is very confused"

The European Commission ruled on Wednesday that France's two-year moratorium on two genetically modified rapeseed developed by Belgian firm Plant Genetic Systems (PGS) was illegal.

The Commission has also began legal proceedings against France for delaying the authorisation procedure for several other genetically altered crops.