Most surgeons expect complete silence from their patients when they are in the operating theatre.

But halfway through a routine ankle replacement procedure, consultant orthopaedic surgeon Dominic Neilsen's patient unnervingly asked: "How's it going?"

The patient, Alex Lenkei, chose to forgo traditional anaesthetic and instead sedated himself with hypnosis.

At one point during the two-hour operation he made a nonchalant comment about the noise of the saw - which was cutting through his bone.

The 66-year-old has now had six operations using hypnosis instead of traditional drugs used to bring about loss of consciousness.

Mr Neilsen, who performed the operation at Epsom Hospital in Surrey, said it was "nerve-wracking" making the first incision.

"He did amazingly well with the whole thing," the surgeon said.

"To be honest, it was just like doing any other operation. Alex went through the process, which took a very short period of time, and he told us he was ready to go ahead.

"It was then a case of getting on and doing the operation.

"It sort of went out of my mind that he was awake and able to correspond.

"He made a couple of comments during the operation which obviously reminded us that it was a strange experience. He commented at one point on the noise of the saws and was just asking how it was going. It was very strange.

"He seemed to just put himself into a trance if you like and just lay there and didn't have any problems at all.

"It certainly was a bit nerve-wracking making the first cut, not being sure whether he would be able to feel it, but once we got through that bit it became very much like doing any other ankle replacement."

Mr Neilsen, who now works at St George's Healthcare NHS Trust, said an anaesthesiologist was on hand in case the hypnosis failed during the operation - which is performed by removing the worn-out ankle joint and placing an implant on the end of the shin bone and the top of the ankle bone.

"The whole set-up was exactly the same as it would have been for somebody under a general anaesthetic," he said.

"If it became painful, or something about his heart rate or blood pressure became unsafe, then he would have been in a position to have anaesthetic within a split second."

Mr Lenkei, who suffers from osteoarthritis, has now undergone six operations without general anaesthesia, including surgery on his hand, a hernia removal and freeing a trapped nerve near his elbow.

The trained hypnotherapist said that while he could feel surgeons manipulating his ankle and could hear all of the noises, he could not feel any pain during the operation, which was carried out on July 8.

Mr Lenkei, from Worthing, West Sussex, said: "This is my sixth major operation with no anaesthetic.

"I asked them if I could do the operation with hypnosis. They agreed because they realised I've got a track record and I'm capable of doing it.

"I'm not averse to anaesthetic - it's just that my pain control is a hell of a lot better than the medical profession's and I heal a lot quicker because my body doesn't have to get rid of all of the chemicals.

"I have been using self-hypnosis since the age of 16 or 17.

"Most doctors are scared because obviously it is not something that they come across in the medical profession, as such.

"The brain is a very sophisticated computer and if you press the right buttons it will do amazing things - if you press the right buttons it will switch certain things off."

He likened his hypnotic state to waking up on Sunday mornings, saying: "You could turn around and go back to sleep or you could turn around and wake up."

Mr Lenkei said he hopes a scientific researcher will investigate his unusual form of sedation if he has to have another operation.