Satires on rock ’n’ roll aren’t exactly two-a-penny but we’ve seen enough of them to judge Peter Cattaneo’s movie with a beady eye. The Rocker is certainly not This Is Spinal Tap, but it is fair to moderate entertainment and Rainn Wilson holds it all together energetically as Fish Fishman, a drummer for the Eighties band Vesuvius, who gets chopped and takes a dismal job — but 20 years later persuades ADD, his nephew’s outfit, to try him out again.

Fishman is a fairly comprehensive idiot stuck in the middle of a midlife crisis. He nearly wrecks the new group, who are young enough to be his kids, with his manic displays. When they finally get used to him, he attempts to show them how to tour successfully by throwing television sets out of hotel windows and generally inducting
them into the ways of musicians.

He’s after revenge, since the bandmates who got rid of him are now famous and he holds a grudge against them. That makes the thought of ADD appearing as their support act seem impossible. Then again, if they do, things might finally happen for them — and that’s how it turns out.

The Rocker varies from out and out farce to more gentle, observant comedy and its tone is often as uncertain as its feelgood ending is unlikely.

The farce is the best value — such as the scene when Fish clambers vampire-like onto the van in which Vesuvius are trying to escape from him. Or when, after a successful gig with ADD, Fish embraces each band member in turn, not realising that he’s sweaty enough to make it a ghastly experience.

Wilson — who plays the Gareth character in the American version of The Office — has decent support from Christine Applegate, Jeff Garlin, Josh Gad, Teddy Geiger and Emma Stone. But it is his film.

What prevents the fullest enjoyment is Cattaneo’s attempt to be heart-warming as well as funny, in the manner of The Full Monty.

Pete Best, the Beatles’ first drummer, himself dismissed as the Fab Four were about to achieve superstardom, has a supporting role. Chad Fisher wrote the songs and, for your information, ADD’s style is “kind of like Fountains of Wayne meets Ben Kweller with some influences from The Cars and Weezer”.

Good heavens, I thought it was Bartok!