Transformers (12A)

To Michael Bay's ever-lengthening charge sheet (Bad Boys, Armageddon, Pearl Harbor) we can now add this dollop of mayhem, a two-and-a-half hour morality play in which good and evil are cast (ho ho) as metal toys. No, really.

Transformers are a race of alien robots – Autobots (good 'bots) and Decepticons (bad 'bots) – that have for some reason located their immemorial struggle to planet Earth. The early warning comes when a US army base in Qatar is comprehensively trashed, sending the Pentagon into conniptions. "We're on a hair-trigger, people," says US defence secretary Jon Voight, little suspecting that the bad 'bots are searching for a teenage boy, Sam (Shia LaBeouf), who has chanced on the key to the universe from a map imprinted on his explorer-grandfather's spectacles. Fortunately, Sam has a getaway vehicle, a Camaro that flips (hallelujah!) into a friendly Autobot, allowing him to impress the hot chick (Megan Fox) and Bay to blow stuff up.

The final hour is basically a demolition derby between moveable scrapyards, with the streets of LA providing a rally stadium. You know that moment when a car suddenly cruises by with a stereo booming out of its windows and blasting a hole in your cerebral cortex? That's this movie, except that the car takes much, much longer to pass out of earshot.