MORTAL ENGINES (12A)

SHORTLY after the digitally-rendered dust settles on an eye-popping action sequence which opens Mortal Engines, the thorny issue of Brexit ripples thousands of years into our desolate future.

"Going into Europe - biggest mistake we ever made," despairs the Mayor of London (Patrick Malahide) as he surveys a post-apocalyptic wasteland dotted with motorised cities mounted on caterpillar tracks.

Adapted from the novel of the same title by Philip Reeve, Christian Rivers' rollicking action adventure doesn't stoke that political fire any further but does make a few mis-steps over the course of two breathlessly enjoyable hours.

The script penned by Fran Walsh, Philippa Boyens and Peter Jackson, engineers of The Lord Of The Rings trilogy, idles in first gear for the initial 20 minutes and grinds through clunky interludes.

More than once, first-time director Rivers falls back on his Oscar-winning background as a visual effects supervisor and allows spectacle to trump substance, aided by an army of digital effects wizards and a vivid steampunk aesthetic.

By happy accident or cynical design, there are echoes of another fantastical saga during the picture's rousing climax - specifically, the thrilling Death Star trench run from A New Hope and a pivotal exchange from The Empire Strikes Back.

Mortal Engines is bolted together from the first book of a four-part odyssey set many centuries after the cataclysmic Sixty Minute War.

Survivors huddle on mobile metropolises fashioned from scavenged parts that "ingest" the resources of rival cities to feed roaring furnaces.

The largest of these behemoths is London, commanded by Mayor Magnus Crome (Patrick Malahide) with guidance from noted academic Thaddeus Valentine (Hugo Weaving).

Masked assassin Hester Shaw (Hera Hilmar) sneaks aboard London and attempts to assassinate Valentine in front of his daughter Katherine (Leila George).

Apprentice historian Tom Natsworthy (Robert Sheehan) intervenes before a fatal blow can be struck and, during the subsequent chase, he tumbles off a gangway and regains consciousness next to Hester in the wilderness.

The fugitives are forced to work together as they encounter famed pilot Anna Fang (Jihae) and a half-human, half-machine warrior called Shrike (Stephen Lang), whose past is inextricably entwined with the girl.

Mortal Engines is a solid opening chapter, which trades in gob-smacking set-pieces and product placement.

"The food of the ancients never goes off. It's indestructible," splutters Hester as she tucks into a popular branded snack cake, which survived the apocalypse.

Hilmar is an appealingly spunky heroine and verbal rat-a-tat with Sheehan's apprentice aviator allows the darling buds of romance to appear gradually in lands poisoned by humanity's greed.

Lang's moving performance sows the seeds of the film's most intriguing and emotionally rich on-screen relationship.

Shrike is unquestionably the most beautiful and heartbreakingly mortal engine on display.

He is the tormented ghost in the precision engineered machine.