Matt Damon and Casey Affleck – grizzled veterans of Steven Soderbergh’s classic caper Ocean’s Eleven from back in 2001 – now come together as stars and co-producers of an expensive but moderate Boston-set heist comedy , co-written by Affleck and directed by Doug Liman. Damon is Rory, a broke ex-marine whose US army therapist Dr Rivera, played by Hong Chau, is treating him for depression and suicidal ideation; he desperately needs cash to pay outstanding alimony and see his son. Affleck is Cobby, a moody ex-con and bar manager who has to stay sober as a condition of parole and so gets neighbourhood kids to blow into the alcohol-test device he has to carry around.

The pair are hired by malign local businessmen played by Michael Stuhlbarg and Alfred Molina to rob the mayor’s re-election victory party, because his safe will be full of dodgy cash donations – but when the mayor actually loses and there’s nothing to steal, the robbery turns into an uproarious fiasco and our two squabbling incompetents wind up having to persuade Dr Rivera to go on the lam with them. The robbery itself is a big moment and there’s a colossal police-car-crunching chase scene.

But in truth, line-by-line and scene-by-scene, the all-important chemistry and comedy between the two male leads is rather underpowered because Damon is so withdrawn and hangdog, and all the back talking and the kibbitzing doesn’t snap the way it’s supposed to. Chau isn’t given much in the script to work with and isn’t in any case much of a natural comic or foil. Affleck himself brings a higher energy level and seems more at ease with the material. Some passable entertainment here but there’s not much adrenaline.

• The Instigators is in US cinemas from 2 August, and on Apple TV+ from 9 August.