He has asked his advisers to examine how this could be done, after receiving the suggestion in an e-mail from a member of the public sent to a special website he has set up on GM foods. It could lead to Fortnum & Mason, and other leading suppliers and firms, having to take steps to control their use and sale if they wish to continue to carry his seal of approval.
This latest stage in Prince Charles's growing campaign against the "gene revolution", comes as he takes up the leadership of Britain's organic farmers. This morning he becomes patron of the Soil Association, the leading UK body pressing for chemical-free agriculture.
The Prince, who farms his own estate at Highgrove organically, has spoken out several times in the last month against GM materials, which are now thought to have found their way into 60 per cent of the processed foods on supermarket shelves. People usually eat them unwittingly, as their GM content is not specified on the labels on the packets.
Last summer, the Prince said that he did not eat GM foods and would not serve them knowingly to his family or guests. He regards them as technologically "unproven, with the potential to cause serious and possibly irreversible damage to wildlife and the environment".
Last month, he set up a special website, on which he says that "we should not be meddling with the building blocks of life in this way". He invited comments by e-mail and has received more than 500, overwhelmingly supporting him.
One e-mail suggested that he should use the Royal Warrant. Companies already have to satisfy environmental conditions before they can be awarded a Prince of Wales warrant or have one renewed; the plan would be to include another condition on GM foods.
The Prince is still building up the number of companies with his seal of approval. So far only 170 carry it, compared with the Queen's 1,180. Existing food producers and suppliers include Shipton flour mill, Twinings Tea, the Nairobi Coffee and Tea company, Hyams and Cockerton for fruit and vegetables, and Fortnums.
Jonathan Dimbleby, page 26