The Cartographer’s Daughter review – handsome period thriller loses its way

Some films announce their budget in the first frame. The Cartographer’s Daughter opens with a crane shot over a rain-lashed 1780s Portsmouth that must have cost more than most British features in their entirety, and for about a quarter of an hour it looks as though the money has been spent wisely. Then the dialogue starts.

The set-up is promising. Eleanor Fane, played by Harriet Dunmore with a great deal of clenched jaw, is the daughter of an Admiralty surveyor who has drowned in suspicious circumstances off the Dorset coast, leaving behind an incomplete chart that half of Europe seems to want. Eleanor can finish the survey, because she has been doing her father’s trigonometry for years, and she can also, it turns out, fence, ride, swim and decode French cipher, none of which the script ever bothers to explain.

The director, Paul Ventris, made his name in television with the Birmingham crime series Jewellery Quarter, and he brings a television instinct for pace that serves the first act well: a chase through a Weymouth rope-walk is genuinely thrilling, and a scene in which Eleanor triangulates a headland from a pitching boat is the one moment the film trusts its own central idea. The trouble is that the plot is required to deliver a new betrayal every 12 minutes, and by the fifth the audience has stopped caring who is lying to whom.

The supporting cast fare variously. Ewan Kincaid, as a naval lieutenant who may or may not be a spy, gives the best performance in the film by the simple method of underplaying every scene the script wants him to shout in. Lydia Oyelowo-Brent is wasted as a smuggler’s widow whose only function is to appear on clifftops. And a late cameo from a French admiral, played with a Belgian accent, suggests that nobody in the edit was listening.

It is a shame, because the craft on display is real. The production designer Tom Haddock has built a Portsmouth dockyard on the Pinewood backlot that smells of tar through the screen, and the costume department’s decision to let Eleanor’s dresses get properly, unphotogenically filthy is the film’s most honest choice. The score, by contrast, never stops, as though the composer had been told that silence was a budget overrun.

The producers have said in interviews this week that they hope the film will do for Georgian naval surveying what previous hits have done for other corners of British history. That is possible: the trailer is excellent, and the film is never boring. But it is never surprising either, and a thriller that cannot surprise is just a costume drama with more running.

The Cartographer’s Daughter is in cinemas now.