The procedure would take about 10 hours

Doctors in the US have already carried out the procedure on bodies donated for medical research.

Now the Cleveland Clinic team will choose a patient whose face is disfigured to receive a "new" face from a dead donor.

The chance it will work is around 50% and experts have expressed safety and ethical concerns about the procedure.

A new face

The recipient would have to take powerful anti-rejection drugs for life, which carry considerable long-term health risks, says the Royal College of Surgeons of England, which formed a working party to look at the issue earlier this year.

Also, it is not known how well an individual and their loved ones would adapt psychologically to a completely new face.

There are a great many questions to which answers are needed

Changing Faces charity

It is hard to predict what the person would look like after a face transplant.

The procedure would involve taking skin and underlying tissues from a dead donor and placing them on the living recipient.

Computer modelling suggests the new face would neither resemble the donor nor recipient's pre-injury self.

The face should take on more of the characteristics of the skeleton of the recipient than the soft tissues of the donor.

The recipient should be able to eat, drink and communicate again through a wide variety of facial expressions and mannerisms.

Picking a patient

The working party said it was not against facial transplants in theory, saying they could offer a major breakthrough in restoration of quality of life to those whose faces have been destroyed by accidents or disease.

You want to choose patients who are really disfigured, not someone who has a little scar

Surgeon Maria Siemionow

But it cautioned: "Until there is further research and the prospect of better control of these complications, it would be unwise to proceed with human facial transplantation."

After a year of discussions, the Cleveland Clinic won approval to go ahead with the operation from an internal review board, which included surgeons, psychiatrists, social workers, therapists, nurses and patient advocates.

Surgeon Maria Siemionow and her team will interview five men and seven women as potential candidates for the 8-10 hour operation.

Dr Siemionow told Associated Press: "You want to choose patients who are really disfigured, not someone who has a little scar."

Yet they will have to have enough healthy skin for traditional grafts in case the transplant fails.

They will be told that their face would be removed and replaced with one from a cadaver, matched for tissue type, age, sex and skin colour.

Charity Changing Faces said: "There are a great many questions to which answers are needed before this extremely risky and experimental surgery could be considered a viable option for patients with severe facial disfigurements.

"It is our view that today's excellent conventional surgery combined with the very best psychological and social rehabilitation programmes can very effectively enable patients with severe disfigurements to live full and active lives.

"The continuing speculation about face transplants is not helpful for people with disfigurements."