A film that can boast the line "You're so full of s**t you're talking mushrooms" is already onto a winner.

But not, apparently, for the film-makers. Nervous of losing the U certificate, they now insist the line goes "You're so full of shiitake mushrooms."

Which is a shame. Because the first line is much funnier and it's rare to see one so good in a kids' film and a sequel at that.

Teens Juni and Carmen Cortez (Sabara and Vega) - "the top spies for their size" - are back and on a mission to the island of lost dreams in this likeable follow-up.

When a top-secret device is stolen from the US President (Christopher McDonald), the sibling spooks are snubbed, while Gary and Gerty Giggles, whose father has just "coincidentally" been made leader of the Spy Kids organisation, are selected for the job.

But with the aid of Carmen's hacking skills, the Cortez kids put themselves back on the case, armed with gadgets that make 007's gizmos look like something out of an Argos catalogue.

It looks like a watch but, in fact, it's the Standard Wrist Unit XP-1, featuring state-of-the-art weapons and an interactive satellite TV. All very well, but there's no room for a clock.

Unfortunately, the gadgets don't work on the island - a sort of hybrid Jurassic Park - and the kids realise that they must face the dangers armed only with their own initiative.

Hooking up with mad scientist Romero (Buscemi), they find themselves fighting off the challenge of Gary and Gerty as well as battling Slizzards (a mixture of snake and lizard) and the usual megalomaniac bent on world domination.

This is surprisingly fresh for a sequel; Banderas winningly sends himself up and, when Buscemi gets in on the act, the laugh quota rockets.

To adult viewers, Sabara may come across as a bit of an annoying pocket-sized Mick Hucknall, but the rest of the young cast keep Irritating American Teen Syndrome (IATS) down to a minimum.

Among the highlights are an over-the-top amusement park (the Vomiter, anyone?), a gorgeously retro-designed dragonfly submarine and a Jason And The Argonauts-style battle with reanimated skeletons.

The special effects are cutting-edge, the script literate and witty but the difficult feat this movie pulls off is that it's never patronising to its audience.

James Trueman