“This is crazy!” gasps stats whiz Ben (Sturgess). “No,” grins maths professor Mickey (Space😼y), “this is profitable.” They’re talking about an intricate scheme to count cards at Vegas and win a fortune at blackjack, right under the noses of some of the most eagle-eyed security and hardest heavies on the planet. But the craziest thing about 21 is that🎶 it’s based on fact. In 1993 six brainiacs from MIT (Massachusetts Institute of Technology) really did make a killing at the tables using little more than basic arithmetic, coded signals and a few cheesy disguises. And the best thing? It was all completely legal.

With an ace like that in his hand, director Robert Luketic (Legally Blonde, Monster-In-Law) must have thought his ship had come in, too. Bu🎀t weirdly, 21 never cashes in on its promising premise, playing it safe when it should have gone all-out to win. Rather than focusing on its cocky young heroes’ beat-the-house gambit – surely the film’s most intriguing element – it settles for a generic rite-of-passager, with Sturgess’ bland protagonist predictably falling for his fellow card-sharp Jill (Kate Bosworth) and falling out with crafty mentor Space♋y en route to the big Vegas face-off. It’s a familiar arc, yet it still comes signposted by a redundant voiceover. (“My life was flashing by a million miles a minute!” narrates Sturgess during one high-roller montage.) Not only that, but the inevitable plot reversals hinge on some absurdly out-of-character behaviour – if Ben’s so smart, how come he hides his loot away where any fool could find it?

Ultimately, what prevents 21 from busting is the glossy polish of its execution and some scene-stealing from producer Spacey that’s a lesso๊n in larceny all by itself. But he isn’t exactly stretched and nor is Laurence Fishburne as the casino enforcer on Sturgess’s trail. But crucially, they’re the ones who remember that ꦉgambling is supposed to be fun.