Some GM crops could be grown in Britain, government advisors have concluded.

In a report published on Tuesday scientists gave a mixed verdict on the future of GM technology.

Officials on the Advisory Committee on Releases to the Environment (ACRE) revealed that some crops could be grown commercially but others should not be planted in UK soil.

ACRE concluded that of genetically modified, herbicide-tolerant beet and oilseed rape could present a danger to the environment.

The findings came from farm-scale evaluations held at secret sites across the UK.

Environment secretary Margaret Beckett also received a report from English Nature on behalf of the statutory conservation bodies.

It too concluded that oilseed rape and beet should not be grown commercially, but that GM maize could be commercialised subject to conditions.

The trials had investigated the possible impact on farmland wildlife that the crops might have.

The two recommendations were based on the results of the farm scale evaluations published in October and a key report in November last year.

Neither had proved to be the ringing endorsement that ministers had hoped for.

Beckett said no final decision had been taken and that ministers would consider with the devolved administrations what their verdict would be.

The key decision will centre on whether Britain should now call for existing EU marketing consents for the crops should be revoked or amended.

"We will now consider ACRE's advice, as well as the advice from English Nature, very carefully before reaching a view on whether these crops should be approved for cultivation in the EU," said Beckett.

"I have said consistently that the government is neither pro- nor anti-GM crops. Our over-riding concern is to protect human health and the environment, and to ensure genuine consumer choice."

Environmental campaigners, who have waged a sustained campaign against the crops, claimed they present a danger to the countryside.

One of the leading opponents of GM crops, which are resistant to some diseases, is former environment minister Michael Meacher.

He claimed the public was being misled.

"ACRE's advice to allow commercial planting of GM maize is flawed. It accepts cultivation of GM maize on condition that the management of the GM crop is limited to that tested in the farm-scale evaluation trials. But that FSE trial for maize is invalid," Meacher said.

"In the case of GM oilseed rape and beet, the FSE trials came to an unequivocal conclusion that the GM crops did cause significantly greater harm to the environment and to wildlife. The government repeatedly said beforehand that if the trials produced that result, they would refuse to commercialise the GM crops concerned.

"And there has also been no testing at all of the health impacts of eating GM foods. Until those tests are fully carried out, there is neither popular support nor scientific justification for growing GM crops in this country."

The announcement followed the prime minister's defence of GM crops last week.

"It is important these measures are dealt with on the basis of science because the biotechnology industry is of huge importance to this country," said Tony Blair.

The Liberal Democrats said the government should reject GM crops outright.

"It would be foolhardy to give the go ahead now, especially while the public remain unconvinced there is sufficient benefit in taking the risk," said Andrew George, the party's rural affairs spokesman.

"The trials considered by ACRE were narrow and focused only on very specific crop management techniques which may not be used in practice.

"New research from the US has confirmed anecdotal evidence that although pesticide use is reduced in the first three years of growing GM crops, over the longer term pesticide use on GMs increase by almost a third - increasing the cost to the farmer, consumer and environment."