What do you do when you have two separate half-ideas for two different movies: one a cynical,  sub-Coen brothers crime caper and the other an ostensibly straight cartel thriller? Well, I suppose you just jam them both together, invite Amanda Seyfried along to a weekend’s worth of filming to paper over some of the gaps and hope that nobody notices you’ve just foisted a tonally inconsistent, narratively garbled, turgidly unfunny mess on an undeserving public.

The Square director Nash Edgerton seeks to blend the border-crossing drama of Touch of Evil with the kind of escalating disarray found in something like Adventures in Babysitting, but succeeds only in delivering a frustrating and tiresomely obnoxious movie that leaves a faintly miasmic feeling of uncleanliness.

David Oyelowo gamely throws himself into a fairly thankless role as good-hearted middle manager Harold, working for an unscrupulous pharmaceutical company, who is sent to Mexico to help oversee a deal to produce a medical marijuana pill. Unbeknownst to Harold, his bosses, played with maximum loathsomeness by Joel Edgerton and Charlize Theron, are in cahoots with a violent Mexican cartel. When the deal goes south, Harold finds himself a patsy in the hands of Mexican criminals, turning to Sharlto Copley’s unhinged mercenary for help and occasionally crossing paths with Amanda Seyfried’s flighty youngster in a minimal subplot, the purpose of which is up for rigorous debate.

To be fair to Nash Edgerton, most of the blame for this mess should fall squarely at the door of screenwriting duo Anthony Tambakis and Matthew Stone who have cobbled together a inconsistent and often mean-spirited script. It shows occasional moments of promise, and minimal instances of narrative flair with the odd twist, but mostly it seems content to just divide its time between crude, underwhelming humour and run-of-the-mill action.

There’s also more than a whiff of sexism running through it. The only female characters to appear for more than a few minutes are humourless, sex-mad homewreckers who drop their knickers at a moment’s notice and fight over the same man with verbal boasts about taking a “cock in the mouth” in an aeroplane toilet.

Biggest victim of all is Oyelowo who shows that, given a decent script and anything to work with, has certainly got a few funny bones. He gives off an easy-going everyman charm as he blunders along in the nice guy role, but he’s sorely let down by a script that figures a gunshot punctuated by an F-bomb suffices for comic genius.

Dir: Nash Edgerton

Scr: Anthony Tambakis, Matthew Stone

Starring: David Oyelowo, Charlize Theron, Joel Edgerton, Amanda Seyfried

Prd: Rebecca Yeldham, Nash Edgerton, Charlize Theron, Beth Kono, A.J. Dix

DOP: Natasha Braier, Eduard Grau

Music: Christophe Beck

Country: USA

Year: 2018

Runtime: 110 minutes

Gringo is in cinemas now.