‘The Ministry of Ungentlemanly Warfare’ could use more brains to go with all its brawn

As war movies go, “The Ministry of Ungentlemanly Warfare” ends up in a kind of no-man’s land, draping elements of “Mission: Impossible,” “Inglourious Basterds” and director Guy Ritchie’s brand of violent action-comedy over the bones of a fascinating World War II true story. The underwritten, somewhat messy results are broadly entertaining if not fully seaworthy from a dramatic point of view.

Given that Henry Cavill (having entered his spy phase, between this and “Argylle”) and Alan Ritchson (“Reacher”) bring their considerable brawn to the festivities, it’s somewhat ironic how thin and un-fleshed-out the characters are. While Ritchie might have been in a hurry to get into the action, it comes at the expense of an investment in the individuals beyond the dire nature of the plot.

That plot involves a secretive version of a nascent special-ops team – given the go-ahead by Winston Churchill himself (an unrecognizable Rory Kinnear) – a real group whose existence remained classified for decades before being detailed in a 2014 book. Adding a pinch of “The Dirty Dozen,” the squad operated under the leadership of a bad-attitude agent, Cavill’s Gus March-Phillipps, who had to be sprung from military prison to lead the group.

Known as Operation Postmaster, the mission played a vital role in the war effort, seeking to sideline the supply chain outfitting Germany’s U-boats, knowing that the submarines’ presence in the Atlantic had, among other things, helped keep the US out of the war. Specifically, March-Phillipps and company are tasked with blowing up a supply vessel that requires overcoming enormous odds, understanding that the British government will disavow them, and the Germans will torture and kill them.

The central quintet (rounded out by Henry Golding of “Crazy Rich Asians,” Hero Fiennes Tiffin and Alex Pettyfer) also receives logistical help from a female spy (“3 Body Problem” star Eiza González) tasked with seducing and distracting the German commander (“Basterds’” Til Schweiger) and a resourceful businessman (Babs Olusanmokun) operating out of the port, on the Spanish island Fernando Po, where the boat is docked.

From the opening sequence, Ritchie (who previously teamed with Cavill on “The Man From U.N.C.L.E.”) works from the well-founded theory that the cathartic act of killing Nazis during World War II doesn’t require explanation. In keeping with a long tradition of movies built around dangerous wartime assignments (“The Guns of Navarone” also comes to mind), the best-laid plans never quite follow the script and inevitably call for improvisation.

Still, the desire to adapt the film to fit producer Jerry Bruckheimer’s blockbuster filmography and Ritchie’s kinetic style keeps dragging it in that direction and away from the grit that would bolster its historical underpinnings. The closing crawl provides a clearer sense of those, in a way that merely heightens a wish Ritchie and his script collaborators had toned down the embellishment.

Those who choose to can enjoy the movie strictly for its red-carpet-friendly cast and muscular mix of a caper with check-your-brain-at-the-door-type action. Even so, a bit more brains to go with all that brawn would have improved things considerably, and maybe even made these gentlemen (and lady) operators seem a bit more special.

“The Ministry of Ungentlemanly Warfare” premieres April 19 in US theaters. It’s rated R.

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