³ÉÈËVRÊÓƵ

Richard Nicholson (THES, September 13) complained that the Nuffield Council on Bioethics report Animal-to-human transplants: the ethics of xenotransplantation did not suggest "how successful animal studies needed to be before starting human trials".

The report proposed an advisory committee on xenotransplantation that would approve any trials involving human recipients and the centres that may undertake such trials. The report went on to state: "No xenotransplantation trials involving human recipients should proceed until the proposed committee [. . .] is in place [. . .]."

To the best of my knowledge no one in this country has suggested that the assessment of the animal trials should be left to the research ethics committee of a single institution.

DAVID SHAPIRO Executive secretary Nuffield Council on Bioethics