The result falls somewhere between a slave-escape drama, an action thriller, a western and even an unexpected kind of superhero film. It’s a winning combination, although Lemmons does not immerse us in the agony and injustice of slavery as such; she puts together a well-crafted movie that is the showcase for an excellent performance from Erivo.

If its aim to inspire and educate inevitably leaves the movie feeling a little classroom-bound, Harriet is still an impassioned, edifying portrait of a remarkable life, and a fitting showcase for the considerable talents of its star, Tony-winning British actress Cynthia Erivo.

Despite Erivo's tenacity in the role, the drama feels more stately and impressive than urgent and affecting. It's never uninvolving though, and the script does a solid job of tracing the formation of a courageous freedom fighter out of a scared runaway.

A thoughtful biopic that grows more involving the more it shrugs off its tendency towards the reverential.

Harriet is a conscientiously uplifting, devoted, rock-solid version of her story. Yet when it comes to putting the audience in touch with what’s extraordinary about Harriet Tubman — not just illustrating what she did but letting us connect with that quest, and with her, on a moment-to-moment level — Harriet is a conventional and rather prosaic piece of filmmaking.