And the vacancies are growing by the year. In a bizarre reversal of the kindergarten game, an extra chair gets put out each time the music stops. There are now more symphony orchestras and opera houses in the world than people capable of conducting them. The reasons for the imbalance are hotly debated - some blame maestro greed, others musical fashion - but the essence of the crisis is no longer deniable.
In an occupation where Leopold Stokowski and Pierre Monteux carried on beating into their nineties, only two eminencies - Sir Georg Solti and Sergiu Celibidache - are now still active beyond 70. The rest have either died young or retired in comfort. Solti has remarked that he is hugely relieved not to be heading an opera house nowadays, as there are fewer than 10 conductors left in the world whom he could rely on to fill a season.
In The Maestro Myth four years ago, I listed a quartet of thirtysomethings who were expected to hold the future of music in their hands - Simon Rattle, Riccardo Chailly, Esa-Pekka Salonen, Franz Welser-Most. None has advanced much since then, and only one other of that generation has come on - the demonic Valery Gergiev, 42, catapaulted by glasnost to run the Mariinsky Theatre.
Behind the Rattle generation, only one man born since 1960 has reached the top - the Italian, Daniele Gatti, 33, the next chief of the Royal Philharmonic Orchestra and principal guest at Covent Garden. The absence of prodigies is a dread harbinger of an empty future. Great conductors have always come through young. Mahler ran the Budapest Opera at 29, Toscanini was 30 when called to La Scala. Karajan was Germany's youngest music director at 27. Today, not one conductor in his twenties has been sighted above the parapet of professional competence.
And not for want of searching. The annual conference of concert agents in London last month buzzed with the question, ''heard any new conductors?", to which the response was a weary shoulder shrug. Agents were heard blaming falling concert audiences on what they call ''presenter decline'' - the lack of credible po-dium stars. The shortage is so severe that some ensembles will try almost any novice on an agent's tip. Often as not, such try-outs end up like two recent dbutantes in the London opera houses, lamely following the orchestra instead of leading it.
A gladiatorial gamut of conducting competitions has sprung up to feed on the scarcity. The judges will be coming round next month to audition candidates, aged 24 to 37, for the Leonard Bernstein conducting competition. Among its contestants will be the losers at this month's Sibelius contest in Helsinki. And any who miss the threshold of both events can always try for the Toscanini trophy at Parma in July or the Unesco-funded Pedrotti prize in September.
At the Kirill Kondrashin comp-etition in Amsterdam last year, I was beset by orchestral players complaining about the finalists - an American, a Taiwanese and a Ukrainian. The winner, Shao-Chia Lu, flash- harryed his way through Petrushka, while the musicians barely looked up from their desks.
If competitions cannot produce good conductors, what about conservatories? All the main academies offer conducting courses, but at least one of them - the Guildhall School of Music and Drama - is considering ending its maestro classes because the candidates are not up to scratch.
Nor has the tendency to fund apprenticeships brought much talent to the fore. Some time ago the Arts Council ran a scheme to attach junior conductors to British orchestras. Unfortunately, big orchestras need big names on their playbills and the kids were given few chances.
The failure of these schemes is hardly surprising. Every conductor of merit has made his own luck. Rattle at 14 assembled an orchestra for a charity concert, Klemperer procured a personal recommendation from Mahler and Solti cadged an intro- duction to Toscanini. Conducting was never just a matter of making music. It required leadership and initiative. This problem has been attenuated by a featherbedded education system that rates equality above excellence.
The education of a maestro once entailed several years of provincial experience before he dared to approach a major orchestra. Now-adays, the first hint of talent brings a rush of agent gold, diverting many a novice from his learning curve into a sharks' pool of unreasonable expectations.
As maestro numbers have dwindled, so the rewards have multiplied. Lorin Maazel is paid DM6 million for 14 weeks' work in Munich. and Mariss Jansons, an Estonian of outstanding gifts, has turned down the London Philharmonic for just 10 weeks' work in Pittsburgh where Heinz Foods underwrites a seven- figure conductor's salary.
So where will the next conductors come from once the Maazels, the Mehtas, the Haitinks and Abbados - all in their sixties - lay down the baton? Gergiev, Salonen and Rattle are clearly in line for top jobs. Gergiev is transforming the Rott- erdam Philharmonic into the best-sounding band in Holland, while Salonen shines each summer at Salzburg. Rattle has stuck with the City of Birmingham Symphony Orchestra, biding his time.
Daniele Gatti is the next high- flier. He has made an exciting start with the Santa Cecili orchestra in Rome and has the backing of the secretive Ronald Wilford, the most powerful conductors' agent.
And several others are rising: Yakov Kreizberg, 35, from St Peters-burg, is the newly appointed chief of the Bournemouth Symphony Orch-estra; Mark Wigglesworth, 30, is learning his trade the provincial way, as head of the BBC's National Orchestra of Wales; Ulf Schirmer, 35, conducting the Danish radio orchestra, has impressed at Salzburg and is recording with the Vienna Phil; and Paavo Jarvi, 32, has landed a co-directorship of the Royal Stockholm Philharmonic.
You may have spotted the absence of women. Sian Edwards, 36, the most promising of her sex, appears to have stunted her artistic growth by staying at the troubled English National Opera. Coming up fast, though, is Simone Young, a 34-year-old Australian protege of Daniel Barenboim, who conducts at Covent Garden and the Met.
This list of newcomers is enough to give encouragement, but conducting is a minefield pitted with ruinous temptations. If the prodigies are to make the grade, they must start by attaching themselves to one orchestra or opera house, to the exclusion of all others and grow together as in a good marriage.
As for the orchestras, there has never been a greater need for them to take a risk on youth. They should drop some of their mega-fee maestros and invest in green shoots and young batons.
! A new paperback edition of Norman Lebrecht's 'The Maestro Myth' is published this month by Simon & Schuster (£9.99).Reuse content