The scientists whose evidence helped to stop the Mathry field trials of genetically-modified maize in Pembrokeshire are now calling for all UK field experiments to be halted as illegal and unsafe.

Dr Mae-Wan Ho, director of the, []Institute of Science in Society; Brian Goodwin, biology professor at the Schumacher College, Totnes; Joe Cummins, plant genetics professor at the University of Western Ontario; and Peter Saunders, biomathematics professor at King's College University of London, say GM contamination has already happened.

DNA from GM crops has already been found in non-GM plants and in pollen and honey protein. It means that field trials threaten the UK's £15bn honey industry.

Dr Mae said, 'Any new technology must be tested, but there are important scientific issues that must be addressed before GM crops can be released into the environment even in the context of testing.

'To conduct field trials before this has been done is both premature and hazardous.

'It is like carrying out clinical trials of a drug before the laboratory tests are complete.'

Their main concern is the spread of mutated genes and antibiotic-resistant genes to bacteria in the soil and in the mouth, respiratory tract and gut of both humans and animals.

The legality and safety of Chardon LL maize, the variety to be tested at Mathry, and other GM crops was strongly contested by scientists during the Chardon LL hearing held in the UK last year.

The hearing was adjourned after a press release issued by Maff on October 30 last year admitted that Chardon LL had not passed the main test required for commercial approval.

The possibility of cross-pollination with non-GM and organic crops as well as wild plants is now generally acknowledged.