Will the waves of protest and anger that have swept through US cities since the killing of George Floyd in Minneapolis make a lasting difference to race relations? African Americans must surely be sceptical. Racism, discriminatory and violent policing have survived all previous efforts to make real the promises of equality and justice for all. Stephen Sackur speaks to the historian and civil rights activist Mary Frances Berry. What will it take to engineer genuine change?

(Photo: Mary Frances Berry Credit: Cheriss May/NurPhoto/Getty Images)