Their meeting place is secret. They have taken a vow of silence until their decision is made, and when the Berlin Philharmonic Orchestra meets tomorrow choose a successor to Claudio Abbado as chief conductor, the atmosphere will be that of a papal conclave. The man who is chosen - and it will undoubtedly be a man - will occupy the most prestigious position in the world of music, conducting 128 of the best musicians on earth.

A secret ballot last week failed to produce a majority in favour of any candidate, and tomorrow's vote will be on a show of hands. It is an open secret that the front-runners are Daniel Barenboim and Simon Rattle but nobody can make a confident prediction about the final outcome.

"Nobody has outed himself as being in favour of one person or another," said one member of the orchestra who broke ranks to speak to The Irish Times last week. "We've discussed all the conductors we've worked with over the past few years, their strengths and their weaknesses. Now we have to consult with ourselves, as it were, and decide who would be best for the orchestra."

When Abbado announced last year that he would not be renewing his contract with the orchestra after 2002, Berliners could not believe their ears. Herbert von Karajan, who conducted the orchestra from 1954 to 1989, and his predecessor, Wilhelm Furtwaengler, remained in their posts until they died. But the Italian conductor said he wanted to spend more time sailing and watching his grandchildren growing up, rather than conduct one flawless performance after another.

Barenboim and Rattle are each believed to command the support of 40 per cent of the orchestra, with the other musicians backing such outsiders as the Latvian Mariss Jansons and Hamburg's Ingo Metzmacher.

Barenboim, who is 57, is favoured by older players, many of whom are hoping to return to the glory days of Karajan with a repertoire dominated by such 19th-century composers as Beethoven, Brahms and Bruckner. Barenboim has lived in Berlin for the past seven years, as musical director of the German State Opera. He has given the opera a thorough overhaul, raising its orchestra to an international level and conducting some memorable productions of Wagner, including a recent Walkure that many critics interpreted as an unofficial audition for the Berlin Philharmonic.

"Barenboim has integrated very well here and he has worked with the orchestra more often than Rattle; he has toured with them. They know him better and many of them love him," according to the Berlin music critic Albrecht Duemling.

The city's politicians would certainly prefer Barenboim, an Argentinean-born Israeli whose move to Berlin was welcomed as an important break with history. Some city officials have privately threatened to stop inviting the Berlin Philharmonic to play at official engagements unless they choose Barenboim.

Rattle's supporters argue that the orchestra must change if it is to maintain its position in the 21st century and that the 44-year-old British conductor has the flair and imagination to lead them in a new direction. As head of the City of Birmingham Symphony Orchestra, he proved that it is possible to persuade audiences to listen to new music as well as old favourites. Rattle has been a popular visitor to Berlin for more than a decade, conducting the Berlin Philharmonic to almost universal acclaim. His latest visit, when he conducted the orchestra in Mahler's Seventh Symphony, persuaded many critics that he is just the man for the job.

But doubts remain, not least because the conductor, whose German is rudimentary, cannot hope to place his stamp on Berlin as he did in Birmingham. "The Birmingham orchestra was a third-class orchestra and he built it up. That doesn't need to be done here, and he couldn't do it here either. He was the only boss in Birmingham but Berlin has a lot of good conductors. One man can't shape it so much," says Duemling.

Some members of the orchestra are backing Barenboim in the hope that he will precipitate a recording boom, creating a bonanza for the musicians. Karajan made three or four recordings a month - more than most orchestras now make in a year. But most recording companies acknowledge that such an output would be impossible today, and some believe that the best way to expand the market is to broaden the repertoire to include more 20th-century composers.

With politicians arguing for one candidate and critics for the other, the pressure on the orchestra tomorrow will be immense, but Duemling believes that it will have no effect whatsoever. "Nobody can influence the orchestra. They'll make this decision entirely on their own."