When the dust (immaculately rendered in state of the art CGI) settled following the first outing of the green ogre with a heart of gold you really felt a legend had been born.

If only they'd left it there. Have you ever heard of Snow White 2? Did Dumbo the Third win a place in the hearts of children across the globe?

The simple answer is no. Their hallowed memory has not been sullied by a series of sequels that owed more to the accounts department than any fresh surge of creativity by the film-makers.

The first Shrek movie was the perfect marriage of rich characterisation, inspired voice work and freshly-minted CGI. The result was an instant classic which could genuinely stand alongside those Disney evergreens.

The sequel was - it has to be said - an enjoyable affair...but no celluloid legend. It just about earned a fresh lease of life by virtue of a knowing nod to a more adult audience and some well-placed sideswipes at our rabid consumer culture.

This time round sequelitis - or the law of diminishing returns - has bitten deeply and this is pretty much indistinguishable from any amount of effects-laden kiddie fare.

When Shrek's amphibious father-in-law croaks it looks like he's going to be handed the reins of power for the kingdom of Far Far Away.

Fearing the responsibility - and learning of his impending fatherhood - he heads off to Worcestershire (cue saucy gags), a medieval seat of learning and home to long-lost heir to the throne, Artie (Timberlake).

Meanwhile, the scheming Prince Charming (Everett) recruits a motley crew of cartoon losers - Captain Hook, Rumpelstiltskin - to help him grab the vacant throne.

With the characters with nowhere seemingly to go, truckloads of Disney stalwarts are bussed into to provide fleeting cameos that serve little purpose.

It's an ogre-egged mess which fitfully amuses by virtue of the strong characters that have made it through from the unequalled original.

Kids will no doubt enjoy it - but not as much as they once did. Ultimately, there's little to distinguish this from a host of other computer-generated also-rans.

This is an animated outing that it literally going through the motions.

Tim Evans