Mr McKenna is being sued by Christopher Gates, who says he has suffered continual mental problems since being hypnotised in 1994.

Mr McKenna told a High Court judge the allegations made against him were false.

Magic spectacles

Christopher Gates: Says he still hears voices

The court heard how during Mr McKenna's stage show volunteers were hypnotised and then asked to mimic the dance movements of the Rolling Stones's Mick Jagger.

Mr Gates, 30, also says that while hypnotised he was given a pair of imaginary spectacles, which enabled him to see the audience as though they were naked.

Nine days after the show, Mr Gates was admitted to hospital suffering from schizophrenia. His mental problems have continued. He says he still hears voices in his head and he is now unemployed.

'Fun show'

Mr McKenna denies negligence and says being hypnotised did not cause Mr Gates's illness.

"My show is a fun show which people choose to participate in or choose not to if they wish.

"If anybody shows any sign of distress, I would ask them if they want to leave the stage," he said.