The Advisory Committee on Releases to the Environment (ACRE) analysed results of GM trials of maize, beet and spring-sown oil seed rape which have taken place at some 60 sites across Britain over the last three years.

"In a sense, we are saying 'yes, but' to the maize and 'no, but' both to the beet and the spring-sown oilseed rape," said Jules Pretty, deputy chairman of ACRE, told a press conference.

"That's not 'yes, no, no'," Pretty said. "That's very important. This is neither a green light for GMs nor a death knell for them."

Environment Minister Margaret Beckett said the findings would be considered "very carefully", alongside other research, before London reaches an opinion on which GM crops could be approved for cultivation in the European Union.

"I have said consistently that the government is neither pro nor anti GM crops," she said.

Environmentalists who argue that GM crops are bad for the environment disagreed with the scientists' positive verdict on GM maize.

"This is bad for farmers, bad for the organic food industry and bad for our countryside," said Greenpeace activist Sarah North.

"Experience in America shows that planting GM maize leads to huge increases in pesticide use," she said.

"The only reason GM maize got through the British tests was because its effect on the environment was compared to a pesticide which is so toxic it's now been banned."

"Giving it the all-clear is like recommending a holiday in Baghdad because it might be safer than Chechnya," she added.

An official report last October found that oilseed rape and beet cultures acted aggressively in the environment and were particularly detrimental to insects, which preferred traditional fields.

But this situation was reversed in fields of GM maize, with greater quantities of weeds on which birds and insects feed being found.

Another report, focussing on the economic impact of a green light on GM crops, was published last July. It predicted only limited benefits over the short term.

More worrying for the British government was the survey of public opinion in September which found an overwhelming majority of consumers were against genetic modification.

TERRA.WIRE