“The Lives of Others,” the compelling new movie about East Germany currently in contention for an Oscar, is the story of two flawed individuals’ quest for moral redemption, but Michael Apted’s “Amazing Grace” raises the bar far higher. It tells the tale of William Wilberforce, an unquestionably good man who set out to redeem the honor of an empire and, in so doing, saved millions of lives.

Born in England in the middle of the 18th century to a wealthy merchant family, Wilberforce (ably played here by Ioan Gruffudd) rose to prominence in a nation that had discovered the virtue of reason and the rewards of science but had lost some of its conscience along the way.

A little more than 200 years before, an appalled Queen Elizabeth I had reacted to the news of an early slaving expedition with the observation that it would bring the “vengeance of Heaven” in its wake. As usual, Heaven remained indifferent. The slave trade flourished and Elizabeth’s successors were quick to take their share.

If God appeared unconcerned and most Englishmen were prepared to either avert their eyes from the evils of the Middle Passage or to profit from it, Wilberforce was undaunted, working tirelessly for two decades to secure the abolition of the slave trade in 1807. Satisfyingly, he lived long enough to see Parliament strike down slavery itself in 1833.

With an exception or two, the filmmakers are honest enough about Wilberforce’s rejection of slavery to make clear that the roots of his disdain for the trade lay not only in inherent goodness, but also in his deep-rooted Christianity. Unfortunately, this honesty does not extend to trusting moviegoers with a sufficiently rounded portrayal of that faith. The real Wilberforce was a man of immense charm, but many of his fellow Clapham “Saints” were a joyless bunch, and so opposed, for example, to the idea of a good night out at the theater that they might even have objected to a film as uplifting as this one.

Such inconvenient fanaticism has no part in a warm-hearted movie such as this. Instead we are shown a kindly creed that is little more than progressive sentiment garnished with loopy transcendentalism. To be fair, this overly simplistic impression is nicely diluted by a scene in which Wilberforce tells one of his more radical acolytes (Rufus Sewell, wild and splendid as Thomas Clarkson) that he has no time for the revolution breaking out in France. But for the most part, there’s little in “Amazing Grace” to illustrate the extent to which Wilberforce’s religion was of a rich man in his castle, poor man at his gate variety.

Perhaps the makers of this movie thought this would be too much for modern audiences to handle. And perhaps they were right. The awkward fact is that Wilberforce believed that Britain’s social order was divinely ordained, so much so that some of his contemporaries complained that the great man cared more about the plight of Africans than that of his less fortunate fellow citizens.

But that’s to be too harsh: Wilberforce’s acts of individual charity may have been the product of a somewhat reactionary paternalism, but they were deservedly the stuff of legend. Nevertheless, “Amazing Grace” would be a more complete film if it demonstrated how there was more than a touch of de haut en bas about Wilberforce and his causes.

That said, there are parts of “Amazing Grace” that are handled with impressive subtlety. For example, the horrific nature of the slave trade is kept mainly offscreen. We catch only glimpses of atrocity: here a report of a distant nightmare, there an empty, reeking ship at berth in London’s docks. It’s effective: The shackles and the savagery disgust all the more when viewed as shadows darkening the Enlightenment, as the monstrosity lurking behind all those elegant Palladian facades.

This approach could be seen to fall into the trap of reducing the victims of slavery into little more than bystanders in their own tragedy, but such a perception would be to miss the cruelty that lay at the heart of this most inhumane of institutions. Slavery was specifically designed to transform men into nothing more than livestock, capable only of having things done to, or for, them. That was the whole wretched point.

So it’s not unreasonable for “Amazing Grace” to tell the story not of the slaves, but of what one man tried to do for them. Needless to say, as in most morality plays (for that’s what this film is), accuracy takes second place to message and not just in the ways noted above. The depiction of John Newton (Albert Finney, an old ham playing an old salt) as the repentant former captain of a slave ship (he became a clergyman and wrote “Amazing Grace” among many other hymns) may give Mr. Apted the reformed sinner that all morality plays require, but the true story was more complicated. In reality, Newton always seemed rather less troubled by his slaving past than the myth now suggests.

Perhaps this is to quibble. The story of William Wilberforce has been overlooked for too long. Mr. Apted has brought this hero back to life, and for that at least he deserves our thanks.