Greenpeace has been accused of trying to intimidate food manufacturers and retailers into participating in a survey it is conducting into genetically modified organisms. A letter from the pressure group, leaked to The Grocer, asks firms to state whether their products contain any GM ingredients or ingredients from animals fed on a genetically modified diet. The letter threatens to blacklist any company that does not clarify its stance on GM foods within a two week time frame. Dated September 6 it says: "If we do not receive a reply to both questions from you by September 25 we will initially put your products on our red' list, those which are genetically modified." The Food and Drink Federation has slammed Greenpeace's tactics. A spokeswoman said: "This is not discussion. This is not negotiation. This is bullying, and it is unacceptable." Greenpeace said it wants to collate the information in a shoppers guide to GM which would be published on the web and in paper form in mid-October. The guide will be divided into three lists: green for GM free, red for GM and yellow for those committed to removing GM from animal feeds. A Greenpeace spokeswoman defended the group's tactics. She said: "We gave people plenty of time. We are not interested in making a separate list of people who are too lazy to respond to the letter." The letter was sent to retailers including Tesco, Asda, CWS, Aldi, and Sainsbury. A Tesco spokesman said: "We were surprised to get this letter as we work closely with Greenpeace on the GM issue." {{NEWS }}