A surgeon who created a two-headed rat says he wants to try the same operation with humans.

The ground-breaking surgery saw the head of a small rat grafted onto the back of a larger rat.

The animal managed to live for around 36 hours.

Italian medic Sergio Canavero wants to switch to human head transplants before the end of the year.

The experiment was reportedly designed to investigate issues relating to blood flow to the brain and the possibility of the immune system rejecting the new organ.

One of the first known cases of such a transplant happened on May 21st, 1908 in the US when Charles Guthrie succeeded in grafting one dog's head onto the side of another’s neck - creating the world's first artificially bicephalic dog.

A paper in the journal CNS Neurosciene & Therapeutics notes that a successful cephalosomatic anastomosis (head transplant) requires "the ability to control long-term immune rejection and avoidance of ischemic events during the head transference phase."

It concludes that a peristaltic pump can guarantee the blood supply of donor brain tissue, while a silicone tube to regulate temperature change can protect the brain tissue.

A team has developed a bicephalic model of a head transplantation to study these.

Science editor with The Times UK, Tom Whipple, told the Pat Kenny Show: "He's not talking about creating a two-headed human, he's talking about moving the head of one human on to the body of another.

"This experiment in rats, which only was a success for 36 hours, is a very, very long way from what he plans to do".

"We're not even really at the stage where you can re-attach someone's own spinal cord to their own spinal cord - let alone take a head from someone and put it on someone else's spinal cord.

"The way he plans to do it is you have someone who's paralysed - probably terminally ill would be the first patient - and then you wait until someone else dies who has as close a matching body as possible.

"You quickly get the two together, you cool them both down...and then you sever the spinal cords of both...and then over the course of an hour, you perform a very, very complicated procedure to re-attach the spinal cord and all the arteries and blood vessels".

"That's the theory, but most neurosurgeons would say even if you could do that, we're so far away from knowing what would actually happen".