When I arrived at the BBC in Manchester to interview conductor Yan Pascal Tortelier, he was still ensconced in rehearsal with the BBC Philharmonic. They were at work on a piece by Lili Boulanger, the first woman to win the Prix de Rome, whose music is little-known these days. They're featuring her work in concert and will be recording it for the Chandos label. Boulanger died at the age of 24 in 1918, and was eclipsed by her long-lived sister, Nadia, who became one of the most influential teachers of the century (Tortelier was among her pupils) and was an important figure in the early music revival, recording Monteverdi (with piano) in the 1930s.

The excerpts I hear at the rehearsal display a welter of influences, a fact jokingly pointed up by a player who finds space during an interruption to knit one of her melodic motifs into a far more familiar shape from the pen of Richard Strauss. It's always hard to know what to make of a snippet of rehearsal - the givens are by no means necessarily obvious. This one seems to be able to combine a relatively easy-going air with serious work. A steel grip in a velvet glove? Who knows? I wasn't there long enough to tell.

Yan Pascal, son of the great cellist Paul Tortelier, started off his musical career as a violinist, working as a soloist, chamber musician and orchestral leader. The family background stamped him in such a strong way - his mother was a cellist too - "that I never, ever in my life thought that I could do anything else. And in any case, I don't know anything else. All I have done all my life is music. And all this could only grow and develop slowly. That's how we go in the family; we are not flashy." The conducting crept in, initially taking up only a small proportion of his time, eventually coming to dominate it, and about five years ago finally excluding the violin altogether. "The violin had limitations for me. Or, if you want to put it another way," he says, laughing, "I had limitations for the violin."

Having been a player, he feels, has had an enormous influence on his conducting. "I remain very, very much a player in my conducting. I don't like the concept of conducting in the strict sense of the word, imposing a technical and technocratic approach to music. I think what we are looking for is having the pleasure . . . sharing the joy of making music together, but really together. That is to say, I `play' with the orchestra as much as the orchestra plays with me. If everything goes well, we all take off together."

It wasn't easy, growing up under such a towering and "terribly demanding" musical figure as the late Paul Tortelier. "As you can imagine, any son tends to resist, not to say resent, but resist at least, his father. It's a Freudian fact, we know that. And of course, I did. There was the Freudian side of it, but there was also the instrumental, the professional side. Everything that my father obtained from his cello, he expected me to obtain from my violin in just the same way. "He was a born cellist. I never was a born violinist. What I would get on the violin was the result of determination and fight and work, very hard work. I didn't get on the violin the rewards which I expected from music and which I get from an orchestra when things go well. Although when things don't go well for a conductor, it can be a nightmare, I can tell you!"

The family did have opportunities to make music together professionally - Yan Pascal's sister, Maria de la Pau, is a pianist. His fondest memories of this activity are of the early years of the Festival in Great Irish Houses in Ireland, when David Laing was running it, and Tortelier concerts were at the heart of its programming. What he remembers with special affection is not just the welcome of the festival, but also what he describes as the special atmosphere of Ireland in June, with "endless sunsets, bringing an atmosphere of timelessness. This is a quality you find in Ireland, which you don't find everywhere."

As a conductor employed by the BBC, Tortelier works his way through a very wide range of music. He sees the major challenge facing orchestras as being one of repertoire. "It is to take on board and to promote or produce an always larger, broader variety of music. Which doesn't mean that we shouldn't hear again Beethoven 5 or Tchaik 4. That's part of the bread and butter. If you take the BBC Phiharmonic, there is so much repertoire this orchestra is covering in a year. On Friday we did Britten's opera Death in Venice, first time in Manchester, in a semi-staged version. On Saturday we had an evening starting with the original Ravel Piano Trio, then my orchestration of it, then the Ravel Piano Concerto, then the Ravel orchestration of Mussorgsky's Pictures at an Exhibition, and then the original of Pictures with Jean-Philippe Collard on the piano. "In four parts," he's quick to explain, "not all at once."

The evening started at 6.30 p.m. and finished at 10.30 p.m. "It's not just a concert, it's an experience. Everybody has heard the Ravel Trio. Everybody has heard Pictures at an Exhibition. Everybody has been to piano recitals where people play Pictures. Here I brought my own orchestration which is a little bit of a one-off." But the juxtapositions are unique. "And that makes a whole evening unusual and special. There are ways of renewing the approach and presentation of music-making rather than relying on the eternal formula of overture, concerto, symphony."

Guest conducting is something which, by comparison, he finds relaxing. "When I am guest conducting, I can take it easy. Wherever I go in the world, I will do one programme in a week, which we will repeat maybe two or three times. I find it so bourgeois, compared with what we do here. We do up to four programmes in a week. That has to do with the fact that we are a BBC orchestra, and the repertoire, by definition, has to be renewed all the time." It's tough work, he says, and personally, now that he's in his mid-50s, he'd like to take it a bit easier. After all, he's had two careers, two repertoires to study and maintain, in one of which he was a late beginner. It's been very draining.

Returning to the subject of renewal, he touches on contemporary music and the move away from, as he puts it, "strict modernism as it was understood in the 1960s". This, he thinks, was due to the fact that "people relate to a certain generosity in music," hence the attraction of styles like neo-romanticism. "That's the problem of today," he says emphatically. "It's that everything is `neo', and not just music. It is a big question in the artistic world, even in the industrial world. If you look at design and architecture, cars, buildings, you will find that things are `neo' ... actually, when I say `neo', I mean `retro'. You borrow a style which used to be itself, you just give it a slightly up-to-date sauce or dressing and you have a `neo' style. It seems that we don't find in all sorts of areas a style of our own today. Look at the design in restaurants, even. We don't seem to find a further stage in our artistic development."

And yet when I ask about unfulfilled ambitions - a question which prompts a lot of thought, because he has clearly found his career so rewarding - he eventually settles on something that's almost exactly a century old. The thing he'd like to do is conduct Puccini's Tosca.

Yan Pascal Tortelier conducts the BBC Philharmonic at the National Concert Hall on Monday in Pictures at an Exhibition and Stravinsky's Firebird Suite. Also on the programme is the world pre- miere of Peter Maxwell Davies' Pemenos with Mermaids and Angels, which will be conducted by the composer.