Grown-ups who avoid children's TV won't know anything about The Powerpuff Girls. They have been supercharging life in Townsville on the small screen for quite some time. They should be as famous as The Simpsons, although their wit and originality is more surreal.

The creative genius behind them is Craig McCracken. When invited to produce a full length feature, he wasn't sure whether to make it for Powerpuff fans and refer to favourite characters, heady with in-jokes, or start afresh, as if from a blank page, so that the uninitiated might be properly introduced. He chose the latter and so the truth of how the Girls came to Townsville is revealed.

Professor Utonium wanted to make perfect, happy children - none of this sexual intercourse nonsense, boffins do it in test tubes - but the naughty monkey Mojo spilt some Chemical X into the mix and they arrived with tiny bodies, big heads, huge eyes that doubled as laser beams, inhuman strength and the ability to fly at the speed of light. They make Superman look geriatric and Batman slow to go.

They don't understand about their powers so that when they walk to school on the first day, they cause havoc throughout the city, simply by fooling around. Next morning's headlines scream "Freak Weirdo Bugeyed Girls", which is really upsetting, because all they want is to be loved. Mojo is quick to see their potential and persuades them to gather the forces of nature to build a Help The Town & Make It A Better Place machine. Of course, he doesn't want anything of the kind. He's after absolute power. He renames himself Mojo Jojo, King of the Apes, which annoys other monkeys, who rebel.

That is only the beginning of the story of how The Powerpuff Girls came to be protectors of Townsville.

What makes the film so unique and special is its animation. At times, the artistry is childlike, at others, a work of supreme imagination. Visually, McCracken opens the bottle and lets every colour of genie loose.

The Girls are funny - let's not forget. Even on a passing asteroid, where they take refuge from civil strife, they bicker about petty things. They are girls, after all, as well as superbeings, although, if you asked them, they wouldn't know what that meant. Mojo Jojo finds out, because he oversteps the mark. Monkeys who want to rule the world will be slapped down by these troublesome toughies called Blossom, Bubbles and Buttercup. That's the Powerpuff way.

It makes you want to cheer.