Research by an American historian at The University of Nottingham could rewrite the history books on the US civil rights movement during the 1960s after revealing that a key racial equality official was also an FBI informer.

Herbert Hill was the highly respected national labor secretary of the National Association for the Advancement of Colored People (NAACP) for more than two decades. The shocking revelation came to light during Dr Christopher Phelps' analysis of Freedom of Information Act re