Viewers of a certain age will remember The Magic Roundabout as an inconsequential yet strangely compulsive five-minute children's TV snippet.

The slightly surreal story of a Dougal the dog, big-booted Florence and Ermintrude the Cow occupied that twilight zone before mum and dad came in to watch the news.

Thirty years later the residents of that charming otherworld find themselves beefed up by state-of-the-art computer imagery and voiced by a gang of Hollywood A-listers.

Extended to feature length, much of the comforting scale of the original is unavoidably lost but, thanks to a sensitive script, the characters shine through.

Zebedee, with vocal duties taken by Ian McKellen, is a sort of Gandalf on industrial springs who is pitched against evil alter-ego Zeebad (Tom Baker).

They're both determined to get their hands on three mystical diamonds that either ensure everything is sunny and rosy... or condemn the world to a new ice age.

When Florence (Kylie Minogue) is encased in a frozen-over Magic Roundabout, her pals must set off to discover the sparklers... but they are in a race with nasty Zeebad.

Dougal, voiced by an engaging Robbie Williams, Ermintrude (Lumley), spaced out rabbit Dylan (Bill Nighy) and shy snail Brian (Jim Broadbent) hit the road.

After Zebedee is condemned to an icy coffin, they have to live on their own wits with transport provided by Lee Evans' eager-to-please Train.

At first thought, the idea of extending the five-minute oddity to a full movie seemed a bit like grafting the plot of Lord of the Rings onto Hector's House.

However, it's surprisingly successful - the characters are constantly fed the sort of comedy lines that work for both children and adults alike.

So we have numerous references to Dylan's "recreational habits" - apparently he's a big fan of grass - while gentler comedy (little Brian's awkward adoration of Ermintrude) will leave the nippers enchanted.

The trio of directors have embraced the spirit of the original (voiced by Emma Thompson's later father) and embellished it in splendid looking style with thoroughly contemporary dialogue.

That's a roundabout way of saying it's really rather good.

Tim Evans