But he was also a realist who dared to dream. Was it really such a coincidence that the piece of music the world came to associate most with Paul Tortelier was Don Quixote by Richard Strauss? The wily old knight, dreamer of dreamers, champion of champions. That was no mere performance he gave - that was a musical manifesto, to fight the good fight for music of all colours and creeds. And Yan Pascal has inherited something of his father's chivalrous nature. He, too, believes in the universality of music, a common language transcending style, period and nationality.
Perhaps that's what his father was really getting at whenever he used the word "international". It is surely significant that only now, aged 51, is Yan Pascal Tortelier gaining recognition in his own country. Because only now is he seen as a truly international figure. Even the French (perhaps especially the French) are impressed by success abroad. And if the local hero can return armed with Mozart and Mahler, Beethoven and Hindemith, Britten and Shostakovich, Elgar and Strauss, so much the better. You see, Papa was right after all.
So what was life with Papa like? Never dull, that's for sure. Yan Pascal speaks of a vibrant household, father and mother (both cellists) holding court to an incessant stream of visiting musicians, many of them family friends, such as the composers Paul Hindemith and Henri Dutilleux. Yan Pascal played the violin, his sister Maria the piano - with father or mother making up the piano trio. But before the music-making came the learning, the theory, the indoctrination. Basic training - the notes and how to attend them - began early, by rote. Papa Tortelier was a stickler for technique. He knew all too well how redundant inspiration was without it. He was going to make sure that his children were well-equipped. Period.
But once the theory was in place and the imagination unlocked, how easy - or difficult - was it to hold one's own in the presence (or the shadow?) of this larger-than-life personality? Yan Pascal speaks of his father's enthusiasm, his encouragement, his inspiration. He was a bit of an actor, a philosopher, a humanitarian. But was it hard being anything other than his son? There is a telling pause as he recalls their second professional engagement together, a performance of the Brahms Double Concerto at the Proms. The review headline read: "Outplayed by Papa". That hurt. Though the hurt, if he's honest, was to some extent offset by the excitement of getting a review at all.
Even so, the penny was about to drop. As a violinist, Yan Pascal was aware of frustrations, even limitations. Being any kind of string player, he inevitably drew comparison with his famous father. For years his father had sat at the left hand of such legendary conductors as Toscanini, Walter, Strauss, Koussevitzky and Beecham. He often spoke of trading places - he occasionally did - but he was far too important a cellist to lay down his bow for a baton. So, he merely passed it on, like an inheritance.
It has taken the younger Tortelier the best part of 30 years to learn his trade - because the learning is in the doing. How else do you hone communication skills? "An orchestra is a strange animal," says Tortelier. "It's potential waiting to happen. When an orchestra `comes along' with you, it's irresistible. When there is resistance - for whatever reason - it's bloody hard. An orchestra must sense that you have something particular to offer them. You have to offer input - or, better yet, inspiration."
And to offer it, you have first to feel it: what you don't feel, you cannot express. It's an old adage, but a true one. Tortelier goes further. He needs to have slowly assimilated a score before he can think of conducting it. He does so from the score, from the printed page, not recordings. He cannot give a downbeat if the music is not already ringing in his head. Members of the BBC Philharmonic - which has been his orchestra now for seven years - will attest to his integrity and passion. He doesn't just beat the music, he plays it. He plays on an orchestra just as he would - and did - an instrument. It's his mind that beats on.
And the phrase "my mind beats on", spoken by Gustav von Aschenbach at the start of Benjamin Britten's opera Death in Venice, has great significance for Tortelier at present. A concert performance of the opera - the first by Britten that he has conducted - will launch a mini Tortelier Festival in Manchester that starts tonight and runs throughout May. The festival is, in part, a celebration of everything that he and the BBC Philharmonic have achieved over the last seven years. Spurred on by a recording contract with the ever-enterprising Chandos label, they have explored repertoire that only the BBC and an independent record company could afford to endorse, let alone encourage. "I guess I've been a winner on both counts," he says, in a French accent that is almost too good to be true. But it is, and so is the charm, modesty and humility that his father has instilled into him. He asks my advice on American repertoire, which he has discovered I know something about. He begs indulgence over the Tortelier Festival. He hopes it is not perceived as an ego trip. He has, he points out, thought long and hard about the content.
One half of one concert is devoted to the music of Lili Boulanger, the younger sister of the legendary teacher Nadia Boulanger, who was Tortelier's professor. Lili was only 24 when she died. Her music, little heard today, seems to scent immortality. She won the Prix de Rome in 1913, at the age of 18. Ravel tried to win the prestigious award three times and failed, says Tortelier, as if to underline just how grand a passion this is for him. Another, of course, is the music of Ravel himself, and in the second concert Tortelier is pitting his own orchestration of the great Piano Trio against Ravel's masterly reincarnation of Mussorgsky's Pictures at an Exhibition - "a dangerous game", he wrily observes.
Picture, if you will, Papa Tortelier, son, and daughter "at home" with the Ravel Piano Trio. An informal read-through. A few bars into the opening movement, Papa turns to his children and says: "You know the quality of sound we are looking for here - try to imagine three flutes, that's the colour." Colour. A Frenchman's prerogative. The opening bars of the Ravel had virtually orchestrated themselves, Yan Pascal says. His father always planned to make an orchestration of this much-loved piece, but once again, it fell to his son to fulfil the ambition. Most of the options were very clear to him. The physical act of playing the piece simply confirmed them. The violin and cello lines pretty well looked after themselves, the enormously challenging piano part more than suggested a fiercely symphonic array of woodwind, brass, and percussion. Ravel always maintained that no trio would ever be powerful enough to convey the trumpety, "heraldic" sound of the finale's grand peroration. The Torteliers agreed with him. Sadly, Papa died just a few months before their dream was realised.
Now Yan Pascal's own sons are collating their grandfather's writings. The eldest - Sebastian, an actor - bears a remarkable resemblance to him. A one-man show? I guess Papa will always be around.
Yan Pascal Tortelier conducts the BBC Philharmonic at Bridgewater Hall, Manchester (0161-907 9000) tonight, tomorrow and on 21/22 May