THE WORLD'S biggest-selling weedkiller, the chemical glyphosate, is facing a European ban after a confidential European Union report showed that it also kills beneficial insects and spiders.

A ban would be a blow to the US group Monsanto, which produces most of the world's supply, usually under the name Roundup. It is central to the group's production of genetically engineered seeds, as Roundup- ready seeds are able to withstand the weedkiller.

Research at Orebro hospital in Sweden also suggests a higher risk of a cancer called non-Hodgkin's lymphoma in those exposed to glyphosate.

In Channel 4 News tonight it is revealed that a confidential EU report says glyphosate should not be approved for use in Europe. EU advisers believe more research is needed.

At the moment each European state can decide which weedkillers it approves, and all have approved glyphosate. But with EU harmonisation on pesticide and herbicide expected in the next two years, advisers have begun evaluating which should be prohibited.

The report, one of several that will form the basis of harmonisation, reviewed evidence and concluded that after glyphosate is used on crops, "harmful effects" on arthropods "cannot be excluded". Itsays the chemical should not be included on a list of approved substances pending more study.

David Buffin of the Pesticides Trust, which campaigns against pesticide use, said glyphosate presented a high risk to certain insects and spiders considered beneficialbecause they kill harmful crop pests. "If you are knocking off the beneficials, it may result in an increase in the insect pests and you have to go in with a fairly invasive insecticide," said Mr Buffin.