http://www.bbc.co.uk/iplayer/console/b01dvw70

This BBC radio documentary explores the narcocorrido (drug smuggling ballad) as a popular genre among Mexicans in the U.S. Denselow, the journalist points to the ambivalence of the the border in the Mexican imagination. He traces the background to 1848 when the U.S. effectively annexed half of the landmass of Mexico including California. Ballads of smuggling across the border date back at least to prohibition, but the first narcocorrido was 'Carga Blanca' (white cargo) a story of drugs, double-crossing and murder dating from the 1940s or early 1950s. While the latterday narcocorridos are banned in Mexico itself for their violent content, North of the border they are seen as, in certain respects, a positive statement of folk identity.