At its peak, The Black and White Minstrel Show was watched by a Saturday night audience of more than 20 million people. David Harewood goes on a mission to understand the roots of this strange, intensely problematic cultural form: where did the show come from, and what made it popular for so long? With the help of historians, actors and musicians, David uncovers how, at its core, blackface minstrelsy was simply an attempt to make racism into an art form - and can be traced back to a name and a date.

• Documentary