Abbreviated to TMNT (presumably because the lead characters must now be Twenty-Something Mutant Ninja Turtles), this computer-animated romp drags the heroes in a half-shell into the 21st century.

Fans of the original series will be in raptures: the new film remains faithful to the legend of the four brothers and their wily rat mentor, and in the closing frames, writer-director Munroe signals a clear intent to resurrect arch-nemesis The Shredder in a sequel.

Action sequences are orchestrated at breakneck pace.

The script promotes the age-old mantras about unity and co-operation.

So when one of the turtles is abducted, a plucky sibling rouses the team by declaring: "I know what we're gonna do: we're gonna rescue our brother and then save New York City!"

TMNT is fast-paced fun, especially for younger audiences, with Mikey Kelley providing most of the humour, surmising that a 3,000-year-old alignment of the stars, which unleashes hell on Earth, is "like Haley's Comet - only monsters come out."

The visuals are polished though not jaw-dropping and only a couple of action set pieces, like a huge battle, make the most of the big screen format.

Vocal performances are solid but poor Donatello serves no dramatic purpose, included presumably for the sake of maintaining the original line-up.

TMNT (PG): Children's/action. Directed by Kevin Munroe. Running time: 86 minutes.

Gazette rating: ***