You'd have trouble arguing that Ralph Fiennes Is frightened of English literature's big beasts. His first film as director, the impressively shouty Coriolanus, tackled one of Shakespeare's more undervalued tragedies. Now he engages with a long-suppressed incident from the life of Charles Dickens.

Derived from a book by Claire Tomalin, The Invisible Woman addresses the novelist's affair with mid-ranking actress Nelly Ternan. If film and biography are to be credited, the relationship led to the break-up of Dickens's already unstable marriage and influenced the bitter ending of Great Expectations.

We begin with a gorgeous sweeping shot of the beach at Margate. Dickens (Fiennes) is dead and Nelly (Felicity Jones) – more than 25 years younger than the author – has married George Wharton Robinson. Her association with Dickens is known, but friends and family seem unaware of its intimacy. She thinks back to meeting at a rehearsal, the beginning of the affair, its effect on Dickens’s home life and – depicted in an unexpected action sequence – a famous train crash.

Those phobic about "heritage cinema" should be aware that The Invisible Woman is frilly and beautiful in the way we expect Victorian period dramas to be. Rob Hardy's camerawork finds all the dark corners. One gorgeous racing sequence appears to nod towards WP Frith's busy painting Derby Day (long the cover to the Penguin edition of Little Dorrit). The costumes have secured the film its only Oscar nomination.

But there is substance here also. Fiennes's layered performance captures the author's virility and energy while conveying the insecurity that resulted from his wretched upbringing. Abi Morgan's script is generous and politically mature in its treatment of the female characters: the increasingly impressive Jones appears withered by Nelly's inability to tell the whole truth, while Joanna Scanlon (the harassed civil servant in the BBC's The Thick of It) makes something tragic of Dickens's troubled wife.

Dickensians will love it. Most everybody else will find is passes the time very agreeably. Meanwhilie, who’s next for Fiennes? Chaucer? Austen? The greats had best have their best hats ready.