Warning: This review alludes to aspects of the stupid plot.

When your drag racing cum heist cum international espionage super franchise (I was hoping to squeeze one more “cum” into that sentence) goes on an involuntary hiatus, with the next entry in this making-it-up-as-we-go-along fest delayed due to a fall out between star Vin Diesel (nominative determinism at its very best) and Dwayne “The Rock” Johnson, what do you do?

Well, if you’re series scribe Chris Morgan (congratulations), you improvise – noting the on screen chemistry between the Rock and Jason Statham, reaching into the world of your movie going twenties, and spinning off those characters into their own Tango and Cash-style, mismatched buddy action comedy. It’s the testosteronic stupidity you love – impossibly beautiful women, fast cars, punch ups and CG-augmented colleterial damage, but with a tighter focus on two characters and a simple seek and destroy narrative.

At least that, one imagines, was the plan. The movie-as-made just about holds onto the template established in a hundred and one unironic ‘80’s actioners, albeit with Vanessa Kirby, as Statham’s MI6 agent sister (inexplicably a similar age in flashbacks but actually 20 years younger than her screen brother), more than the fuck object/damsel in distress of yesteryear. She’s still the excuse for some willy waving between the leads of course – Stath threatening the Rock’s territorial integrity by promising, Kurt Russel style, to show her his moves. But despite a promising start, with both leads hamming up it nicely in the antagonism/mutual loathing department, it’s not long before the quest to bring in Idris Elba’s cyber-enhanced human becomes numbingly rote.

Perhaps it’s because there’s too much emphasis on setpiece construction and not enough on the characters trading barbs, but long before the end Morgan seems to have given up on providing the quintessential Hobbs and Shaw experience, rather stretching these two characters (with unwanted and unnecessary support from Ryan Reynolds and Kevin Hart) over a now familiar Fast and Furious sequel scenario.

All concerned might have got away with it, had it not been for that pesky forth act. That’s right, one hour and forty minutes into the movie we’ve gone through the standard set up, complications, climatic confrontation at the villain’s HQ formula, only to discover the film has another 40 minutes to run. Who was the story consultant, Michael Bay?

This forth act belatedly picks up Hobbs and Shaw’s backstory – that most depressing of Hollywood clichés, the familial restoration. Transporting the action to, er, Samoa – and recalling the end of Superman II, the plan is to lure Elba’s robobastard to a remote part of the world to face Hobbs and his family of native engineers/rugby players, with Shaw bringing up the rear while rebuilding the relationship with his sister.

The characters’ preparations for this confrontation mean the movie effectively stops – no longer propulsive, no longer keeping the titular mercenaries in tight focus. It’s a technically proficient but bladder-testing end to what had been an otherwise slight entry into a slight franchise.

Revelations in this final quarter include that a billion dollar man can be defeated when forced to fight two people at once, and that the entire movie might have been a Tokyo Drift-like entry out of sequence – set further in the future, meaning the forthcoming Fast 9 will fill in the blanks. That’s not a bad tactic for generating some anticipation/online interest in the next ensemble movie, but a little more old school focus on character would have been appreciated in this one.