Medieval music, Mongolian chant, and sitar are but three of the many ingredients poured into Tan Dan 's opera Marco Polo. Richard Coles discusses the work as it gets its UK premiere and asks why the story of Marco Polo still has a resonance in the West's relationship with China today. And 20 years after its first performance, Harold Pinter 's Betrayal is seen as one of the landmark plays of our time. Richard Coles discusses Trevor Nunn 's new production, which opens tonight at the Royal National Theatre. Producer Robyn Reade