I am not sure if the author Anthony Horowitz is a clever chap or a cynical opportunist. He is the creator of the highly successful Alex Rider series of books for young readers. If you have managed to miss them, they are espionage tales for boys who think Harry Potter is for girls. Judging by his screenplay for Stormbreaker, he has taken Ian Fleming’s James Bond and repackaged him for a new generation: he has made Bond cool for kids.

The hero of Stormbreaker is 14-year-old Alex Rider (Alex Pettyfer), a mini-me Bond manqué without the bonks and the birds. The nearest we get to that is a girl called Sabina Pleasure (Sarah Bolger). And there’s not a sharp suit or a shaken martini in sight. But everything else is present and correct: exotic baddies, MI5 goodies, a flash car with an ejector seat, gadgets and action scenes galore.

The film opens with Alex at school, having to tell his classmates about his family. His parents are dead, and he lives with his uncle, Ian Rider (Ewan McGregor), and his housekeeper, Jack Starbright (Alicia Silverstone). Alex is annoyed that Uncle Ian doesn’t spend more time with him and is always away on business. Hello — doesn’t Alex have any friends of his own? Maybe not. He certainly doesn’t have Bond’s charm when it comes to women. He asks Sabina if she would like to get together over the weekend, and when she says she can’ t and suggests they meet next weekend instead, Alex just snorts “Whatever” before taking off on his bike, the big sulkpot.

Then Alex is told that Uncle Ian has died in a car crash because he wasn’t wearing his seat belt. But Alex knows his uncle always wore his belt, so he decides to investigate what really happened. He discovers that Ian was a spy for MI6, murdered by a Russian assassin, Yassen Gregorovich (Damian Lewis). MI6 eventually persuade Alex to work for them. His mission is to find out what the computer billionaire Darrius Sayle (Mickey Rourke) is up to. Sayle has built a revolutionary computer called the Stormbreaker and plans to give one to every school in the UK. So, posing as the winner of a competition in a computer magazine, Alex goes to Sayle’s mansion in Cornwall to find out what the sicko is really doing.

It’s strange to see a new film that hasn’t one original idea in it. But what about having a 14-year-old spy — that’s something new, isn’t it? Well, it could have been had the screenwriter, Horowitz, and the director, Geoffrey Sax, allowed Alex to be a vulnerable or scared teenager. The casting of 16-year-old Pettyfer doesn’t help. He handles the action scenes with great gusto, but the rest of the time he’s stiff and incapable of expressing any emotion. He looks like a pretty boyband member. We get no sense that he is really too young for the job of espionage. Once he begins his mission, he comes across as just another action hero. As one exasperated army officer says of him, he’s “no child, he’s a lethal weapon”.

Some younger readers might think, oh, shut up, grandad, chill out and enjoy the film — it’s just a bit of fun. But why can’t “fun” films for teenagers also be fresh and inventive instead of endlessly recycling the old stuff? Come to think of it, why can’t fun films for adults do the same? Sax, who has worked mostly in television, shows that he is a proficient if not inspired director, one who moves the story at a good pace and throws in some nice fast cuts and those edgy techno-paranoia shots that Tony Scott loves to do. And Stormbreaker is a watchable film. The action sequences lack invention, but they are executed with panache. I suspect serious fans of the books will find the film version’s tongue-in-cheek jokiness a little irritating. It has that self-consciously British playfulness that echoes The Avengers and Austin Powers. But the real letdown is in the bad-guy department: Rourke gives one of the laziest, most undistinguished performances we have seen in a while. He really ruins his screen time through his indifference to the role.

Still, this is a very British affair, with a host of familiar faces (Stephen Fry is the Q-like figure in charge of gadgets; Bill Nighy does a predictably wonderful comic turn) and familiar sights: Life Guards on horseback, the Houses of Parliament. So we have here some silly fun that’s diverting, if never distinguished.

Stormbreaker, Three stars
PG, 90 mins