The �200,000 action against the TV hypnotist was brought by furniture polisher Christopher Gates.

Mr Gates, 30, claimed to have suffered psychiatric injury as a result of being hypnotised on stage by the star in March 1994.

During a show Mr Gates was hypnotised into believing that a special pair of spectacles would allow him to see the audience naked.

Christopher Gates: Hypnotised to see audience naked

Nine days after the show at the Swan Theatre in High Wycombe, he was admitted to hospital suffering an acute schizophrenic episode.

Mr McKenna denied negligence and contended that Mr Gates's illness was not caused by hypnosis.

Anthony Scrivener QC, for Mr Gates, said that in clinical conditions, a hypnotherapist would inquire into a patient's medical history to ensure no harm was done.

He added that in stage shows there were no such safeguards.

Even if Mr Gates was already suffering from schizophrenia, he did not know it.

Mr McKenna's pre-show warning that people suffering from mental stress should not volunteer would have had no effect, he added.

Roger Henderson QC, for Mr McKenna, said there was no evidence that Mr Gates had suffered serious stress under hypnosis.

He added that Mr Gates had volunteered, enjoyed the experience and was the funniest participant and the star of the show.

"He made a bargain - he exchanged silliness for being centre stage," he said.

Stage shows 'would cease'

In his closing submissions at the end of a two-week hearing in London, Mr Henderson said the damages claim boiled down to the question of whether Mr McKenna negligently accelerated Mr Gates's mental illness.

He added: "In practical terms, however, it has far wider ramifications because a probable consequence of such a conclusion would be that stage hypnosis, and other stage and television shows involving active audience participation, would cease in this country.

He said that Mr McKenna was a "careful and caring" entertainer and that there was no proven link between hypnosis and schizophrenia.