When he was 12 he heard a performance of Beethoven 's Fifth Symphony conducted by Erich Kleiber , which gave him the ambition to become a conductor .
He learned the piano but , when he was 14 , he heard Erich Kleiber conduct Beethoven 's Symphony No. 5 and he immediately wanted to be a conductor .
He wanted to study biology but his eyesight meant he could not use a microscope , so he did engineering instead .