Campbell Aird has a high-tech false arm

Campbell's arm holds a battery and on the inside are sensors which are able to pick up a muscle tensing in the shoulder and move the arm.

But Campbell does not get any "feedback" from his arm to his brain, so he finds it almost impossible to make subtle movements with any type of precision.

Our hands contain three main nerves, two major arteries and 27 different bones. Even simple movements involve the co-ordination of up to 60 different muscles.

Real hands are extremely versatile and it is this complexity which robotic hands have such trouble replicating.

More of the brain is devoted to controlling the hands than any other part of the body.

Matthew Scott's blood vessels had to be connected to those in the donor hand

There are 2,500 nerve receptors in each square centimetre of the fingertips, so it is extremely difficult for an artificial hand to give its recipient anything like the sensation of touch.

The advantages of having the real thing are so great that it is hardly surprising that people like Matthew Scott, from near Atlantic City in the US, have chosen to have a dead person's hand in preference to a robotic one.

Matthew lost his hand in an explosion and had a prosthesis fitted.

It helped but there were still many ordinary things that it could not do.

Newspaper report

On holiday in Britain, his wife happened to read a newspaper report about research taking place into hand transplantation.

Matthew was chosen by the Jewish Hospital in Louisville to be America's first hand transplant patient.

The main problem with transplant surgery is that of rejection.

A large team of surgeons worked on Matthew Scott's transplant

The body's immune system launches a massive attack on the "foreign body".

This is a very important defence mechanism, a way of fighting infection and disease, but it is a real danger for transplant patients.

Powerful drugs are used to suppress the immune system but they can have serious side-effects, such as cancer, diabetes and high blood pressure.

It has been estimated that one in 10 people receiving a hand transplant will die after 10 years as a direct result of taking immuno-suppressants.

Eighteen surgeons took 14 and a half hours to connect the arteries, veins, nerves and bones of the dead donor's hand to Matthew's arm.

He still cannot do everything that he could with his original hand and he will have to continue taking immuno-suppressants for the rest of his life, but he is delighted with his new hand and thinks it's all worthwhile.

His wife Dawn said: "I can tell by looking in his eyes his anger and his frustrations have gone.

"He has started to do things that he loved to do - he can play the drums now. He is much happier, he is much more at peace with himself, he is much more balanced."

World's first

New Zealander Clint Hallam, the world's first hand transplant patient, has not been so lucky.

Clint Hallam's new hand was attached to his stump

Clint received his new hand in France in September 1998 and now wants the limb removed.

He is having quite serious rejection problems; his new hand is slowly dying and barely functions.

What's more, he is distressed by how many people, even close friends, avoid him because they find his new hand repulsive.

He said: "My first thoughts when I saw my hand was that I thought it was a miracle.

"But one of the hard things to accept for me is that I am almost more handicapped than when I just had one and half hands."

The surgeon who carried out the operation says he is now prepared to amputate the limb.

British surgeon Dr Nadey Hakim, from St Mary's Hospital in London, said Clint Hallam had been a poor patient who had ruined doctors' work by not taking anti-rejection drugs.

Superhuman - Spare Parts is broadcast on BBC One on Sunday 22 October at 2210 GMT.