The search for the next BBC Young Musician reaches its penultimate stage as the category winners from strings, percussion, woodwind, brass and keyboards compete for three places in Sunday's grand final. Josie D'Arby is joined by acclaimed violinist Nicola Benedetti, BBC Young Musician Winner in 2004, and world-famous trumpeter Alison Balsom, artistic director of the Cheltenham Festival, who won the Brass Category in 1998.The category winners competing in the semi-final are: Matthew Brett, a 17-year-old percussionist from Cheshire, Maxim Calver, 18, who plays the cello and studies at Yehudi Menuhin School in Surrey, and Robert Burton, an 18-year-old saxophonist who is a first-year student at the Royal Academy of Music. They will be joined by the winners of the brass and keyboard category finals.