They branded the government's plan to control GM farming in the UK as a worthless publicity stunt.

The code contains a list of "dos and don'ts" for farmers and food processors who intend to grow GM crops.

But campaigners say it fails to address concerns about the safety of GM crops.

The code would only be voluntary and has been drawn up by SCIMAC, a group of organisations which represents farmers, the seed trade and biotechnology companies.

Robin Maynard of Friends of the Earth

Friends of the Earth campaigns director Robin Maynard said the proposals were "ridiculous".

Food Minister Jeff Rooker defended the move, saying the government had had to opt for voluntary measures.

Ministers wanted regulations in place before UK farms started growing GM crops and that there would not be enough time to pass legislation to do this, he said.

Food Minister Jeff Rooker: "Laws cannot have been done in time"

The code appears likely to be approved by a Cabinet committee on Wednesday and would come into effect immediately.

Penalty points

Under the proposals, penalty points, similar to those used for drivers, would be given to anyone breaking the rules.

Those who collected 12 points over three years would be disqualified from growing GM crops for a fixed period.

Food producers are being handed a voluntary code

The code also contains rules about what information seed developers should pass on to farmers and that farmers should give to food companies who buy their crops.

It sets down how farms should keep records of what crops they have grown and also standards of best practice for cultivation.

'A PR paper exercise'

Mr Maynard said: "This isn't regulation. This is a voluntary code of conduct put forward by industry and the only reason they have done this is the public in Britain is so opposed to GM cropping.

"Over two thirds of people don't want GM crops grown at all.

"This document was leaked to Friends of the Earth and others so it suggests that people within government don't think it's satisfactory and it's pretty much a PR paper exercise."

He added that the code failed to deal with concerns about the effect on the countryside of use of weedkillers which could be used with GM crops.

Its only advice on the subject was to name conservation groups which farmers could contact if they were concerned.

The provisions dealing with the risk of organic farms being contaminated by GM crops in neighbouring fields were also inadequate, he said.

There was scant guidance on how GM farmers should deal with their neighbours and the rights of non-GM farms.

"The SCIMAC code doesn't really say what farmers are supposed to do except tell their neighbours then it's left to the courts," he said.

Critics of the code also say a pro-industry bias is obvious in the penalty points proposals.

They say it is bizarre that more points would be awarded for hoarding GM seeds - which could potentially hit the profits of seed companies - than for spilling seeds and allowing GM material to grow.

Laws would 'take too long'

But Mr Rooker defended the code, which he said would be enforced by independent spot checks on farms.

Jeff Rooker: Restrictions are needed

He said a government consultation, which ended in 1997 demonstrated a widespread desire for special regulations to cover GM crops.

This had not left enough time to get regulations passed in UK and European law before the current trials of GM crops got underway, he said

"We didn't want there to be the position so there would be the consents for the crops, so legally they could be grown, without there being special rules."