Although Wilberforce has won public acclaim for finally outlawing the trade, it was Thomas Clarkson who provided him with much of the data that he used to back up the cause. The film is one of contrast: between the pious young divinity student, straight out of University, and the bawdy taverns and rough slave port where he conducted his fact-finding. Clarkson 'grows up' as the film develops: he acquires street wisdom and finally realises the most effective way to win the crusade.