The Royal College of Surgeons said they were "not adverse" to the surgery and recognised it as a possible future treatment.

But they said more consideration was needed on the psychological impact on the recipient and the donor family.

They also said they needed to look at the long-term risks associated with the drugs the patient would have to take for the rest of their life to stop them rejecting the face.

Plastic surgeons in the US and UK are vying to become the first to carry out a facial transplant.

The recommendations were part of a report by the College's working party - and will be a blow to surgeons looking to pioneer the technique.

Researchers looked at issues such as whether the patient would look like the donor, the physical and psychological risks they faced and how they might deal with other people's reactions to them.

Last week it emerged that plastic surgeon Peter Butler and his team at the Royal Free Hospital in London had received letters from 10 people who had expressed an interest in becoming a recipient of a face transplant.

During the lengthy operation, eight different blood vessels, four arteries and four veins would have to be removed from the donor.

Dr John Barker, who leads the American team looking into the surgery, said it was right to press ahead with the operations, which could benefit patients with severe facial disfigurement.

He told BBC Radio 4's Today programme that recipients would not necessarily end up looking like the donor.