Their letter to MPs was intended to put the case against a ban on GM crops and reassure the public its safety was the top priority.

The move comes after a series of high-profile scare stories on the issue and a rise in fears about the new crops.

Paul Tyler: "Government acting like Tories on BSE"

Liberal Democrat food spokesman Paul Tyler said the government was now reduced to "blind panic".

He said: "This joint letter from five Cabinet ministers is all too reminiscent of the shock joint statement from Douglas Hogg and Stephen Dorrell on BSE, three years ago.

"That too marked a Government climbdown and that too led to a collapse of confidence."

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The letter was signed by five key ministers: Deputy Prime Minister John Prescott, Health Secretary Frank Dobson, Cabinet Office Minister Jack Cunningham, Agriculture Minister Nick Brown, and Secretary of State for Trade and Industry Stephen Byers.

It said: "Throughout history, new scientific advances have raised new fears.

"Some of these have proved irrational, others have proved well-judged.

"The government's first priorities are to protect people and the environment. But we must do so in ways that do not deny to our people the healthcare, environmental, economic and other benefits that flow from technological advances.

Greenpeace took their protest to Downing Street

"That would be an abdication of the responsibility placed on us."

The five-page letter is accompanied by a 50-page factfile about the development of GM-foods and the government's policy.

The move comes after protesters dumped four tonnes of genetically-modified soya beans outside Downing Street and the government appeared to signal it might bow to a ban on the crops.

Greenpeace activists targeted Tony Blair's official residence after his spokesman said the prime minister was happy to consume GM food.

BBC Chief Political Correspondent John Sergeant reports on how the government has handled this issue

"We are taking these GM soya beans to one of the few homes in the UK where they want to eat it," a spokeswoman said.

Later on Thursday six people were arrested for trespass after they allegedly tried to stop a shipment of GM food from being docked in Liverpool.