It looks like the end for Jan Compton when she is decapitated in a road accident. But her fiance, mad scientist Bill Cortner, is not prepared to give up on her. He recovers her head and revives it in his secret laboratory, keeping it in a tray of liquid. Then he sets out to find a new body for her - by murdering another woman.

This is the plot of the 1962 horror film The Brain That Wouldn't Die. Now Dr Cortner's scheme could actually become possible (albeit without the murder).

Even in the 1960s, the idea was not new. In 1908 an American team transplanted the head of a dog onto the body of another and managed to get blood to flow between them - but only very briefly.

In the 1950s similar operations were carried out by a SovietRelating to the Soviet Union, a powerful group of communist republics, the biggest being Russia, that existed from 1922 to 1991. surgeon called Vladimir Demikhov. The dogs were able to see, move and lap up water, and survived for up to a month.

Then, in 1972, the American neurosurgeonA surgeon specialising in the brain, spinal cord and nervous system.   Robert J White managed to attach the head of a rhesus monkey to the body of another. The creature was able to hear, smell and see, and even tried to bite one of the researchers, but was hugely distressed and died eight days later.

Now an Italian neurosurgeon, Sergio Canavero, claims that it will soon be possible to take the head from a sick person's body and attach it to the body of someone who is healthy but brain-dead. He says he has already managed to perform transplants on dogs, monkeys and dead human bodies.

Such experiments are hugely controversial. Robert White was attacked as "Dr Butcher" by animal-lovers and in 2016 the European Association of Neurosurgical Societies declared that transplanting human heads was unethical. Canavero, however, has pursued his experiments in China, which has less rigorous standards.

The idea raises many questions. One is whether such a procedure could really work on humans. It involves severing the spinal cord, and since there is no known way of reconnecting it, the patient would end up paralysed.

A counter-argument is that many patients are already paralysed, and at risk of several organs failing - so a transplant could prolong their lives. But Dr Allen Furr, the author of a book on the subject, believes they would suffer chronicA condition which recurs over time, or lasts for several years. pain: "The quality of life would be tragic."¹

Even if an operation were successful, the patient would face an identity crisis: what would it feel like to have someone else's body? And, says Dr Furr, "If the body donor had had children, do the children get to visit the body?"

There is a debate, too, about whether our sense of self exists only in our heads. Writing in Popular Mechanics, Ashley Stimpson explains that "the second-largest bundle of nerves in our body is the one in our guts. The enteric nervous system, sometimes called the 'second brain,' is made up of more than 100 million nerve cells...

"Although it can't solve a crossword or make hard decisions like the brain in our skull, the enteric nervous system does have a profound influence on our emotions."

But are they really a good idea?

Yes: It would be wonderful if a young person with terrible disabilities could have a new body or an older person's life could be prolonged. We should celebrate the amazing ingenuity of scientists.

No: The main beneficiaries would be the powerful people who could afford such an operation. With their heads transplanted onto a succession of younger bodies, they could dominate the world for centuries.

Or... Canavero's latest idea is to transplant a person's brain to a cloneTo create an exact genetic copy of an organism or cell. , which would overcome some objections. But whether humans could or should be cloned is another area of passionate debate.

Soviet - Relating to the Soviet Union, a powerful group of communist republics, the biggest being Russia, that existed from 1922 to 1991.

Neurosurgeon - A surgeon specialising in the brain, spinal cord and nervous system.  

Chronic - A condition which recurs over time, or lasts for several years.

Clone - To create an exact genetic copy of an organism or cell.