The artistic director of the Vienna Boys Choir has resigned in a row over how often the choir should have to sing for its keep.

Agness Grossmann leaves two years after returning from a glittering career in Canada to take over the 500-year-old school.

Professor Grossmann said: “I can no longer carry responsibility for the well-being and the artistic development of the children with a healthy conscience.” She had failed to secure cuts in the concert workload to make room for changes in the musical and general education at the choir school, Immediately after taking over the choir in October 1996, Professor Grossmann set about modernising the institution with far-reaching reforms, including “concrete measures to relieve the burden on young artists”.

Parents had complained that their children were forced to work too hard and referred to the monk-like regime at the school.

Professor Grossmann wanted a reduction in concert tours and routine performances to allow more time for leisure, conventional schooling and musical training. She also said the boys, most of whom board, should spend more time with their parents.

Karlheinz Schenk, executive chairman of the choir, rejected allegations that the boys were working too hard and said that Professor Grossmann’s plans to ease the burden by forming a fifth choir were not practical.

Grossmann has left one radical mark by admitting girls into the choir kindergarten school. She said she looked forward to the formation of a Vienna Girls Choir as the girls proceeded into the upper levels of education. Another innovation was to insist that the choir ocassionally perform soul and rock music. She said their musical education could not neglect music with which they had such rhythmical affinity.