Back in 2013, the Jackass team conjured up Bad Grandpa, with Johnny Knoxville slapping on old man prosthetics and acting incorrigibly. It was, as you might expect, utterly puerile. But at least it wasn’t as reprehensible as this cruel, lazily scripted and ultimately spineless effort from British director Dan Mazer (I Give It a Year) and screenwriter John Phillips, which knocks another nail into Robert De Niro’s comedy coffin. He plays the aptly-named Dick, a recently widowed septuagenarian who wants to get back on the horse – or several horses, preferably – and ride.

Collaring his soon-to-be-married straight-arrow grandson Jason (Zac Efron) to drive him from Atlanta to Florida, Dick is soon masquerading as a college professor and partying with spring breakers while trying to bed Aubrey Plaza’s grad student Lenore. Tagging along reluctantly, Jason flits between moping after Shadia (Zoey Deutch), a girl from his past, and trying to keep his psycho fiancée Meredith (Julianne Hough) at bay (all the female characterisations are one-dimensional and offensive).

Soon enough, Jason has succumbed to an all-night orgy of crack-smoking, nudity and granny-snogging – leading to one of the film’s funnier sequences, where he wakes up on a beach with just a cuddly toy covering his modesty. Efron has some comedy chops and plays the transitions well, though any fan of De Niro from his heyday will likely sigh after seeing him reduced to masturbating-to-porn, using the n-word and awkwardly rapping at a karaoke night.

If the film has (fleeting) moments of shamelessly low-brow, American Pie-style appeal, even this is undone by the lame final act, which sees Jason reconsider his marital options and Dick attempt to make amends for being a lousy parent (turns out, he had a secret job that kept him away from Jason’s father, played by Dermot Mulroney). Thus, the crass gags give way to something more sweet-natured, which is jarringly out-of-step with what’s come before and won’t please anyone looking for a dirty laugh-fest.

General release from Fri 29 Jan.