Conventional oilseed rape seed that contained a low level of unapproved GM seed was sown at a trial site in Somerset, an investigation by Defra's GM Inspectorate has shown. The GM seed was of a type that is approved for import and food and animal feed use in the European Union, but not for cultivation. No GM material has entered the food chain.

The seed harvested from this trial, and an adjacent trial of spring oil seed rape, has been identified and is now being securely stored while the GM Inspectorate continues its investigation. None of the seed has been transported onwards to other destinations and the investigation has confirmed no other oilseed rape crops were grown in the vicinity at the time of the trial.

In September 2008, Defra was informed that a low level of genetic modification was detected in experimental seed of a new variety of winter oilseed rape entered in National List trials. This was detected before any of the National List trials were sown but a commercial trial involving seed of the same origin had been sown in Scotland. The case in Somerset has been identified as a result of a tracing exercise carried out after this initial discovery.