You won't be feeling sleepy: Paul McKenna is bringing hypnotism to the small screen for a psychological version of Blind Date. Roger Parsons found himself mesmerised

'LADY DI's in on it,' says Sir Gary Neave, rocket scientist, meeting the interviewer's gaze with that look of make-my-day sincerity he reserves for chat show appearances. Sir Gary, had just revealed the existence of life forms on Saturn, visible through 'microscopes' based on earth, and was now waxing confessional about his affair with the Princess of Wales, telling us how he met her 'in a club', that 'she doesn't beat about the bush . . . asked straight out . . .'.

Welcome to The Hypnotic World of Paul McKenna, which will occupy the prime time entertainment slot on the ITV network this Bank Holiday Monday. 'Sir' Gary is one of ten volunteer subjects in the spotlight and has been told that he is appearing on a chat show as the world's greatest liar. Earlier on, when invited to enact a slice of his everyday 'real' life (3.30 on a typical Monday afternoon) we'd seen a ham-fisted mime of a man on the phone arranging the delivery of car bumpers.

Gary's reaction to being shown a tape of his own behaviour has been recorded and inserted in a Blind Date style box: 'The more I lied, the more relaxed I felt.' He remembers hearing the audience laugh and 'getting the hump' with them. These 'documentary' inserts do a lot to anchor the show and rescue it from accusations of trickery. They remind us of the category of thing we're watching: being a prat under hypnosis, not just being a prat.

What you won't see in the TV special - except in a baffling 60-second montage - is the process of selection and hypnotic induction which occupied a third of the available studio recording time. This is partly because it's simply not as entertaining as someone snogging a broom, and partly as a precaution. Hypnotism can and does work via the television and nobody wants a law suit.

The first man to hypnotise via television found this out by mistake and to his cost. In 1946 the BBC invited hypnotist Peter Casson to test his technique in front of the cameras at Alexandra Palace. At the first attempt, five of the 12 studio volunteers went under. But so did a studio engineer who was watching a monitor in a room across the corridor. Casson then deliberately attempted to hypnotise an audience of six watching in another room - four fell asleep and two of them needed waking. It was concluded that 'a broadcast would not be advisable.' As The Lancet put it: 'They are probably wise to avoid the chance of some susceptible person taking an action for alleged harmful affects of hypnotic sleep or even missing an appointment. We commiserate Mr Casson on his embarrassing success.'

Mr Casson is still at it. He can be found in the small ads of The Stage: 'the old master' followed by the acronym FESH. He has successfully combined his stage work with private hypnotherapy clinics in London and Yorkshire, hospital research into painless childbirth and ownership of Club Baba and Club Kiki. FESH stands for the Federation of Ethical Stage Hypnotists. It is fair to say that Mr Casson is not very impressed by Mr McKenna. 'Let's just say that I know what I'm talking about and he doesn't'

The two men are from different ages, different eras of entertainment. McKenna is young, 29, an ex-DJ. His patter is quick, his management canny. He has a winning line in interviews (where the descriptions of him all seem to use 'small', 'dapper' and 'salesman'). He talks about how little of the human brain we use, how he helps to reveal the creative potential of the unconscious. Facts and insights are repeated in conversation after conversation with unnerving consistency (perhaps this is what he meant when he said once that we all live in a trance called the English language). His greatest coup was persuading Westminster Council to grant a licence for his show at the Dominion Theatre, which has built a cult following through word of mouth, celebrity endorsement and the simple fact that people want to see it more than once. It was not so easy to get to see the Old Master in action. When I first called Peter Casson he had one engagement for the year (he has since booked several more) at the Grand Theatre, Wolverhampton.

On arrival at the Grand, a hand-written notice regretted that a lecture demonstration would take the place of the advertised programme. The tall figure in the spangly-bodiced conjuror's one-piece who took the stage was a much gaunter, older version of the man on the programme cover but yes, it was Peter Casson, now 71. His warm-up was glacial: we were treated to a tirade against the small-minded local authority which had had the temerity to add additional safety conditions to those suggested in the Hypnotism Act of 1952.

The irony is that Casson himself suggested those guidelines to the Home Office in the first place (the 'lecture demonstration' turns out to be a way of exploiting a loophole of his own creation). In fact he considers himself personally responsible for the act which enshrines the stage hypnotists and lay hypnotherapists right to practise at all. The act came about as a reaction to what Casson calls a 'put-up job' attempt by a group of doctors to get a bill through Parliament banning anyone but the medically qualified from using hypnosis. According to Casson, Lord Kaberry talked the first bill out as a personal favour to him, and then got him to make suggestions for ethical and procedural guidelines in a new bill which became law.

Casson's grumbles about his younger rival are mostly on the grounds of hypnotic ability. He points out that McKenna's subjects tend to be young, and generally chosen from the most hypnotically susceptible of the volunteers. His own induction methods are faster, almost instantaneous, and do not require the laborious selection process. The act is a demonstration of power, a presentation by the master hypnotist, the puppet master of the sleeping bodies. He is impatient with those who break the trance, brisk to the point of rudeness. He doesn't seem to bother with the lubricating chumminess of the chat show. Actually this is perversely refreshing. He's a Yorkshireman, but doesn't trade on it. There is a quality of straight dealing and a very English sense of humour. He can look back over a long and successful career and tell you drily that his last employer was George VI and his last job was killing Germans.

If McKenna is a manipulator of the modern media, Svengali to the Karaoke generation, Casson's act has a whiff of national service and the polished woggle. He remembers the music halls and the clubs, entertaining the troops, queues round the block and packing them in at the Swansea Empire. He gives credit to the Boy Scouts Movement and is clearly proud of his training in psychology and the respectability he has earned through his medical work. He is anxious that hypnosis be seen for what it is, a useful tool in the right hands.

In fact respectability is the high ground they both claim. It is the key to popular success now that hypnotism has largely shed the trappings of the occult and its reputation for charlatanism and quackery. They both distance themselves from the unlicensed acts, the stag and hen nights, the raw onion eating, groin scratching and the sheep shagging. Both emphasise the acceptance of hypnotism by mainstream medicine, once the enemy. Peter Casson feels he can honestly claim to have helped put hypnotism on the map. Paul McKenna has put it on television, where it will inevitably evolve to survive.

Television's great strength is the close-up. Suddenly the puppets have expressive subtleties. We can study the almost childish sincerity these compliant and instantly suggestible actors bring to everything they do. McKenna's act depends on drawing the right kind of extroverted behaviour from members of the public, and this can be achingly funny. It is also very wise. Light entertainment can use up the material of a lifetime in a single show, but we never seem to tire of the Blind Date, Beadle school of ritual humiliation.

In neither act do you really get a sense of how they do it. Casson is better at it, but by now that is missing the point. The new wave hypnotic act is not about the demonstration of power, it is about unlocking the imagination. McKenna claims to create a psychologically limitless environment, which is a bit over the top. While so much of the show depends on the mimickry of television's own established forms (the quiz show, the chat show, the game show), the limits to the imagination are staring you in the face. But he shouldn't be afraid of the ordinariness he unearths. The hypnotic world of Paul McKenna is a pyschological talent contest in which we see people performing what they think is required of them without having to take responsibility for their actions.

While the basic effects are known, scientists still can't agree about what is unique about the hypnotic trance or even if it is a seperate state at all. Electro-encephalograms show no difference between the brain waves of those who are deeply hypnotised and those who are awake. It may be that McKenna's greatest skill could be in the reassurance he gives us that this genuinely mysterious business has some connection with our ordinary selves.

(Photograph omitted)