The BBC's June Kelly: "Some manufacturers say its impossible to label everything"

A survey shows that many people want all packaging to say whether food has been genetically-modified in any way.

Research for Which? magazine conducted by the Consumers' Association investigated 32 common foodstuffs, both supermarket own label and well-known brands, which were not labelled as containing any GM ingredients.

Eight of the samples contained soya and maize that were guaranteed GM free but all of the other 24 could contain GM products even though they are not required to state this on the label.

The association wants to ensure that shoppers who do not wish to consume GM foods are given an alternative and the freedom and information to choose.

'In the dark'

Which? Editor Helen Parker said: "There are so many loopholes and exemptions that, even if the current labelling laws were fully enforced, consumers would still be left in the dark."

Recent food scares make labelling all the more important

The association launched its campaign to put pressure on Agriculture Minister Nick Brown for more rigid labelling rules by unveiling a billboard opposite his Whitehall office declaring: "Isn't it time labelling was modified too?"

A European Union regulation, introduced in September last year, means that GM ingredients only have to be labelled if they contain determinable levels of protein or DNA.

However, other soya-derived ingredients such as lecithin, commonly used in the manufacture of chocolate bars and cakes, do not have to be labelled along with other GM ingredients which contain no protein or DNA.

Children's food

The research showed that the makers of eight of the products, including Kellogg's Cornflakes and Heinz Rice Pudding for children used GM-free sources of soya and maize.

But the other 24 products remained under suspicion of containing ingredients derived from GM sources.

A poll of 2,000 people carried out by the consumer group showed that support for more stringent labelling laws was overwhelming.

Some 94% of those questioned said they wanted to see any ingredients which had been modified in any way clearly labelled.