The European Commission (EC) has failed to make public a study on GM farming that suggests that the crops would not be economically viable for farmers.

The report suggested that the introduction of GM crops would mean “unsustainable costs of production” for growers of conventional oilseed rape, maize and potato, who would also see the costs of their crops rise by up to 41%.

It was produced by the Joint Research Centre, and a letter from the Centre’s director-general, Barry McSweeney, which accompanied the report when it was sent to the EC, read: “Given the sensitivity of the issue, I would suggest that the report be kept for internal use within the Commission only.”

According to the Daily Telegraph, EU Agriculture Commissioner Dr Franz Fischler has referred to the study, but so far failed to make it public.

A spokesman for Dr Fischler told the paper that the report is likely to be published “in the next days or weeks”.