The leader of the band

A wet remembrance Sunday in Birmingham, with police and fans at war in the streets after a football derby, is no place to go looking for creative futures. Still, the air in Symphony Hall is electric and the house is packed as the cultured half of the city awaits the first sight of its incoming music director, a novice so obscure that no one is quite sure how many S's to print in his name.

Andris Nelsons bounds out from the wings holding a baton before him like a fencing rapier and leaps into a Strauss Don Juan that, of an instant, changes the sound of the City of Birmingham Symphony Orchestra (CBSO) as I know it.

There is a beach-white brightness, an intense heat and a whiplash silence that speaks far louder than music, like the hush that falls the moment after a bomb goes off. From the look on the players' faces as they listen to each other you know this is no everyday effect.

In Dvorák's New World Symphony, Nelsons strips out the advertising clichés of boys on bicycles delivering bread and makes the overworked score smell hand-baked and oven-fresh. At the end, when Nelsons summons his soloists to take a bow, the players stick to their seats and continue applauding his performance. "Thank you for all your energy," he beams at them afterwards.

"Now we have to keep this up all the time." "We're totally bowled over," confides one musician afterwards. "We're in love," blushes another. Even the so-called pre- Rattleites who have played in Brum since the industrial era walk out into the drizzle with a spring in their step.

Andris Nelsons, 28, is tall, gangling and untouched by hair stylists or PRs. He is not even sure how his name should be spelled. "It could be from the Swedish Nilsson," he surmises, "or, of course, from the Great British Admiral", who (as every Latvian knows) liberated Baltic shipping lanes in the Battle of Copenhagen in 1801. Either way, Nelsons is the new hot rod of the world podium, the lightning conductor..

His introduction to music came at the age of four when his mother founded Riga's first early music ensemble - no small revolution under Soviet rule. He found himself singing English Renaissance music - Tallis, Byrd, Gibbons - to verses from the King James Bible.

At five, he was taken to the Riga Opera, which Wagner directed in the 1840s, to see Tannhäuser. "I couldn't stop crying for some days," he says. "I knew I could not live without this." He was sent to music school at six and played trumpet in the orchestra. When a teacher was late to rehearsal, he stepped up, all of 16, and took the baton. "It felt good. I was not nervous.

It was what I needed to do." One night a trumpet player fell sick in the visiting Oslo Philharmonic, led by Latvia's most famous son, Mariss Jansons.

"The general manager was running round the hall before the concert crying, 'Can anyone play trumpet?' so I stepped up." Performing Symphonie Fantastique unrehearsed earned him a meeting with Jansons and a chance to become his private pupil, "a dream come true - his approach to music, his fantasy, is so close to my soul".

Nelsons's ruminative, gravelly, slightly repetitive way of speaking is a reflection of his idol's mannerisms, as are some of his finger gestures in performance.

But there are few similarities of interpretation in Strauss and Dvorák, where Jansons achieves power and precision while Nelsons brings out subtleties of internal conflict.

At 24, Nelsons was named chief conductor at the Riga Opera, where for the first time in a century he performed Wagner in German, catching the ear of foreign critics. Word began to buzz. The CBSO chief executive Stephen Maddocks heard him conduct in Munich and, having booked him for next March, decided that his players needed to see him sooner.

Birmingham was seeking a new chief and has a habit of falling in love on first sight.

In 1979, the CBSO picked a Liverpool lad, 24 years old, with curls to cry for.. By the time Simon Rattle left in 1997, Birmingham had the best concert hall in Britain and the best band outside London.

Rattle's successor, signed at his second rehearsal, was Sakari Oramo, a smooth-cheeked Finn, barely 30 and so new to the baton that he held down a fiddle player's job at Helsinki Radio. Oramo sleeked up the string tone (never Rattle's forte) and variegated the programming before calling time this year, giving the band a full season to test such young contenders as ENO's Ed Gardner, Glyndebourne's Robin Ticciati, the Israeli Ilan Volkov and the rising Czech Jacob Hrusa. In the event, none of them got a look-in.

Nelsons arrived to conduct an acoustic test in the £35 million refurbished Town Hall just before the season started in September. Before the day was out, Maddocks was getting texts from players, demanding: "Why haven't you signed him yet? Get a move on." "We knew in about half an hour," says an old-timer. "Andris stopped us to explain a passage we'd played dozens of times and when we tried it again it sounded completely new." "For me," says Nelsons, "the human chemistry is essential. Making music is so sensitive I need to feel more than 70 per cent of the players are with me.

This orchestra, they like to work hard.

I am so excited that they like to work the way I do, to create ideas. We forget everything, for the music." We are sitting in a room built to Rattle's design, with a well-stocked bar, and Nelsons is running through regenerative ideas. He wants to have a dialogue with audiences, to hold post-concert discussions about music and life, "when my English is good enough". In rehearsal, fumbling for a word, he asked for an "inert" sound. He strikes me as a man who knows exactly what he wants, and how to get it.

He scorns routine cycles of anniversary composers and enjoys pairing works from different eras, the Italian madrigalist Gesualdo, for instance, with a post-modern minimalist. He once twinned Richard Strauss's Hero's Life with Haydn's mass in honour of Admiral Nelson, two contrasting aspects of human courage, domestic and imperial.

Nelsons spends much of his spare time and cash buying CDs, books and scores, turning up last summer at a Jansons Prom with £3,000 worth of shopping. His girlfriend, a soprano at the Riga Opera, was singing Mimi in Amsterdam this week but has cleared next September for his grand inauguration.

In Latvia, his Birmingham coup is headline news and critics from several European cities flew over for his debut.

Bewildered by the speed of events, Nelsons struggles for context. "The first thing anybody outside the UK knows of Birmingham is the orchestra and the hall," he ventures. "That's what I grew up with. I don't even know the names of the football clubs. This is a great place for music - for the future."