''When I hit the 50-year mark I decided: that's it, I'm going to do a university course,'' Vidal said.

''I was thinking of studying history or philosophy, then Procter and Gamble (which bought out his company's product division in 1985) said: 'How would like to have your work exhibited around the world over the next three years?' ''Nobody in my craft has ever had the opportunity to do anything like that, so I thought: why not? ''We've done Europe and North America and we'll be going on to China, Australia and Central and South America.'' This weekend it's Hongkong's turn and no effort has been spared to make Sassoon 50 a memorable event.

Yesterday saw the gala launch of the Asia Look featuring two beauties each from Hongkong, Taiwan, the Philippines, Singapore and Thailand - every pair given a distinctive hair style - and tomorrow, the general public is invited to view the Sassoon 50 Exhibition at the Academy for Performing Arts.

Divided into seven sections, it traces the amazing Sassoon story from the 50s to the present day, with special emphasis on the most important influences, from the Bauhaus school of design to women's expanding roles in society.

At the heart of it is the one-time shampoo boy from London's East End who has never forgotten the tough times, despite global fame and megabucks.

''I took elocution lessons for three years to get rid of my cockney accent,'' says Sassoon - no relation to the famous Sephardic Jewish family of pre-war Shanghai, though he shares their faith.

Born to a mother from Kiev - ''93 now and living in California'' - and a father from Salonika who abandoned them when Vidal was just five, he spent most of his childhood in a Jewish orphanage, then was sent to Wiltshire as a wartime evacuee.

At 14, his mother ''literally took me by the hand and marched me off to be apprenticed to a local barber'' and in 1948 at age 20, he joined the Israeli Army.

''My year in Israel gave me a sense of dignity. I finally found myself,'' says Sassoon. Years later, the experience inspired him to found a centre for the study of anti-Semitism and related bigotries at the Hebrew University, Jerusalem.

''It draws scholars of every faith and deals with every brand of xenophobia,'' says Sassoon.

''Religion is wonderful on paper, and sounds and feels marvellous, but kills millions of people. The righteousness of evil is a devastating force.'' To Vidal Sassoon, philosopher and educator, can be added philanthropist, best-selling author, TV host and above all, revolutionary.

As the fashion world wallows in 60s nostalgia, it is worth remembering that this still fit and youthful-looking 65-year-old was there at the start. Indeed set the fuse.

''It was in early 1963 that Mary Quant and I put on the show that really changed everything.

''The night before, I'd cut the models' hair - it took till 2am - and nobody saw them till the show began at Mary's Knightsbridge shop at 10 the next morning.

''All the London press was there and when the girls came out in Mary's minis - nobody had seen clothes that short - and my geometric cuts, there was complete uproar.

''All the members of the old brigade were aghast, while the young ones ooh-ed and aah-ed. There are those moments when something happens and it did that day. The revolution had begun.'' Sassoon recalls how on spotting him in Paris at the salon of the famous Alexandre a week later, one of the dowagers of the London press very pointedly said, ''Now this is real art'', but by the mid-60s the battle had been won.

It was then he took it to the States - ''London was three to four years ahead of America; they were still back-combing and teasing'' - where he gave seminars from coast to coast.

''The really significant change in the 60s was that hairdressing became hair-cutting along with colouring, perming and styles that could be taught. It was part of that whole sense of liberating women, of setting them free from all those constrictions.

''My aim was to make women look and feel more beautiful; to carve shapes in their hair that gave them a modern, individual look. I wanted them to feel: I am free to use my mind in any way I choose. I can even be the Prime Minister.

''That liberation came about through a group of people who genuinely loved women, not through off-the-wall types with odd sexual preferences.'' The ''carving'' that typified those famous Sassoon landmarks - among them, the Greek Goddess, the Veil, the Wedge, the Asymmetric Cut and closest to home, the Nancy Kwan - had its origins in her husband's boyhood dream, reminded Rhonda Sassoon.

''He wanted to be an architect, but the family was too poor. It's always been his first love,'' said the Cincinatti-born former model and accessories designer who majored in Art History at Ohio University.

Like wife No 1, Beverly Sassoon who co-authored the best-selling A Year of Health and Beauty, she is a glowing advertisement for the Sassoon ideal: good looks plus brains and an impressive creative streak.

Their new home in the hills outside Los Angeles has been a major Ronnie project.

''I wanted something that had the simplicity of Bauhaus, but all I was shown was Disneyland Deco or Mediterranean/Colonial/ Cape Cod.

''Everything was either bizarre or bastardised, then finally we found the place. We've used a designer, not a decorator. It still amazes me that there are people who shed everything when they move and get a decorator in to start all over again.

''In the Mid-West where I grew up, people's homes grew up with them.'' She's a forthright woman who doesn't mind admitting that her hair has been touched up to hide the grey - ''two bands of it on either side''.

Vidal Sassoon, whose styles have graced some of the world's most famous heads from Catherine Deneuve to Rod Stewart, who wielded his shears on Mia Farrow for Rosemary's Baby and has been called equal in influence to Christian Dior, is equally honest.

''I never cut hair anymore - absolutely no exceptions. The reason is that I know I couldn't do it as well as I used to and I always vowed I'd stop at the top.'' He's still the undisputed king. As the other Ronnie led the way to the elevator outside the Presidential Suite, he asked the question that had been burning inside.

''Tell me,'' said the butler, ''does Mr Sassoon have anything to do with the shampoos? What? He is the Vidal Sassoon? Oh my God!''