Overview: From the Royal Albert Hall, Katie Derham introduces the Mahler Chamber Orchestra, a truly international orchestra whose players come from 20 different countries. Formed in 1997 it has rapidly established a reputation as one of Europe's best ensembles. Under conductor Daniel Harding it plays symphonies by Schumann and Sibelius and is joined by the Liverpool-born pianist Paul Lewis for a performance of Mozart's Piano Concerto no 25.