We all think we know what 'The Blues' means - whether it's feeling down in the dumps or a musical genre that links Muddy Waters through to The Rolling Stones.

But what is it really? What makes The Blues the Blues? And where did it come from? Tom Service is joined by jazz pianist Julian Joseph to discover its earliest African-American origins right up to current-day Blues music and its influence on classical musicians.

Whether we're talking Gershwin's Rhapsody in Blue, classical composers using 'Blue' notes or that feeling of melancholy - the Blues has often found its way onto the concert stage too. Tom looks back across classical music history to find that actually music has had a bad case of the blues for many centuries.