Rivers of Blood is one of the best known but least understood speeches in British political history. In this documentary the fragments of filmed speech that survive are brought together and Enoch Powell's argument is examined in detail. Powell prophesied that mass migration would lead to segregation and communal violence, but the incendiary nature of his language dominated the headlines. His core argument was largely ignored. This film examines Powell's character and the fears that drove him to make his fateful speech. We see how his words bitterly divided the nation, and see why Powell was cast out into the political wilderness, with his speech becoming a byword for racism. On the 40th anniversary of Rivers of Blood, this film explores the controversial claims and counter-claims surrounding one of Britain's most divisive politicians, and perhaps the most infamous speech in modern political history.