Twenty years ago this week, on 17 May 1954, the first shot was fired in the American blacks' war for civil rights, not on the riot-torn street of some northern city but in the United States Supreme Court. In what has become known simply as the Brown Case, Chief Justice Earl Warren ruled that segregation was unconstitutional. It was a shattering blow to the Deep South, leading directly to the freedom riders, murder, riots and the rise of Martin Luther King. Now, 20 years later, to the wry delight of many Southerners, the civil rights battle has moved through the scorched ghettoes of the mid-60s race riots to the northern cities in general and Detroit in particular. This summer, the Supreme Court will pass judgment on a case in Detroit that will be as significant in 1974 as Brown was in 1954. Jeremy James has been to Alabama in the Deep South and Detroit in the Deep North to examine the first 20 years of American civil rights and asks - how far have the blacks really come and how far ha