The dispute between the US and EU over GM foods at the WTO is examined in terms of the issues it raises about protectionism and environmental protection and precaution. The issue of whether GM, GM Derived and Non-GM foods are equivalent to each other is examined using data from a national choice modelling study in the UK. These categories of food are critical since they underpin the EU's new food labelling regime which it hoped would defuse the WTO dispute. The results are analysed using a Bayesian mixed logit model which allows greater flexibility in the modelling of preference distributions. This is particularly crucial where, as in this case, bi-modal distributions are identified with some indifferent or mildly averse to GM foodtypes while others are strongly averse. A strong finding of the analysis is that people treat ingredients derived from GM crops (but free from altered DNA) as equivalent to GM ingredients. This supports a labelling regime based on process rather than simply product and suggests considerable consumer benefits from the EU's new GM labelling regime.