Directed by Michael Apted. Starring Ioan Gruffudd, Albert Finney, Youssou N'Dour, and Michael Gambon. Rated PG.

As I write this review, the T-shirt, jeans, and sneakers I'm wearing are all probably the result of some form of indentured servitude. The same could be said of the components of the computer upon which I am typing, and of the radio that is playing in the background. Nevertheless, slavery in the sense of chained Africans being carried in lethal holds to overwork and death in the New World is a thing of the past, and Amazing Grace, Michael Apted's new movie, was made to celebrate the 200th anniversary of the abolition of that form of human exploitation within the confines of the British Empire.

Unlike, say, Steven Spielberg's Amistad, Amazing Grace is not a movie of brilliantly constructed dramatic set pieces. It's not the kind of film where links of naked tribesmen are shown sinking into the green depths of an unforgiving ocean. It is, rather, a film about ideas, and the painfully slow parliamentary process that led to one of history's few clear-cut victories in the never-ending war against profit-driven oppression.

The hero of the piece is, of course, William Wilberforce (Ioan Gruffudd), the physically frail but mentally unbreakable member of Parliament who proposed bill after antislavery bill in the House of Commons to MPs who had millions invested in West Indies sugar plantations and who were about as interested in seeing their crops harvested by freemen and women as the Bush administration is in having Iraq's oil industry nationalized for the exclusive benefit of the local population. Nevertheless, Wilberforce—who also had a lot to do with the creation of the Royal Society for the Prevention of Cruelty to Animals—persisted, and with the aid of a handful of Quakers, admirers of the French Revolution, and friends in high places (notably William Pitt the Younger), was eventually able to push his ideas through the back doors of Westminster (justice, as always, being achieved by "sneaky" means).

While parts of Amazing Grace look like Masterpiece Theatre boilerplate, the film is ultimately redeemed by intelligent writing and quietly affecting acting.

Screenwriter Steven Knight knows how 18th-century Parliament works, and his "villains" (Lord Tarleton; the Duke of Clarence) are every bit as rhetorically dextrous as his heroes. Knight's dialogue likewise sounds entirely authentic, without seeming artificially archaic. He also has the good sense to let us know that Wilberforce is a reformer, not a radical, and that his desire to change the world does not extend to full-scale social transformation (even if he does experience the occasional pang of guilt when he compares his own luxurious country house to the hovel of the average peasant).

Gruffudd is fine as Wilberforce, but it is the actors in the smaller roles who really show what they can do. As Barbara, William's future wife, Romola Garai comes across as a classic Regency beauty with the brains of two Jane Austen heroines and the heart of three. Albert Finney is equally good as John Newton, composer of the hymn "Amazing Grace" and former slave-ship owner with 20,000 dead Africans on his conscience. (Never before have the words "a wretch like me" held such chilling significance.)

Again and again, we are treated to minor emotional epiphanies, and Amazing Grace is fated to consume more than its fair share of tear-stained hankies. The good news, though, is that every one of these tears is well earned, and that here, emotional release is not an easy cop-out but an entirely legitimate celebration.