THE robots in disguise receive a welcome and sweetly sentimental reboot in the sixth instalment of the Transformers franchise.

Travis Knight, Oscar nominee for the exquisite stop-motion animation Kubo And The Two Strings, replaces Michael Bay in the director’s chair for a family-friendly origin story cast in the mould of The Iron Giant.

Bumblebee unfolds before events of the original Transformers with a touching friendship between the titular Autobot and a grief-stricken girl played by Pitch Perfect alumnus Hailee Steinfeld. The 22-year-old actress delivers a sincere performance, capturing the awkwardness of a teenager who hears her pain echoed in the songs of The Smiths.

Production designers go to town with late 1980s period detail – amusingly, the Decepticons are credited as architects of the world wide web – to a soundtrack that bops to the catchy melodies of A-Ha, Rick Astley, Tears For Fears and Steve Winwood.

Spectacular action sequences punctuate the heart-tugging narrative but director Knight wisely doesn’t attempt to out-muscle Bay, whose penchant for special effects left previous tours of duty feeling bloated.

A bruising showdown against the dastardly Decepticons on planet Cybertron forces Optimus Prime (voiced by Peter Cullen) to sound the Autobot retreat.

B-127 (Dylan O’Brien) crash-lands in California and makes a hasty escape from armed forces.

He transforms into a yellow Volkswagen Beetle shortly before his circuits shut down.

Plucky teenager Charlie Watson (Steinfeld) salvages the car and in the safety of her garage, she is stunned to discover the weather-beaten Beetle is a shape-shifting robot. She christens him Bumblebee and agrees to keep her mechanised pal safe.

Meanwhile, Decepticons Shatter (Angela Bassett) and Dropkick (Justin Theroux) trace B-127 to Earth and begin the hunt

Bumblebee is delightfully lean – it’s the only film in the series to clock in under two hours – and balances aftershocks from the fall of Cybertron with Charlie’s growing pains.

Steinfeld tenderly conveys the depth of her heroine’s affection for her childlike robo-companion, who serves to protect the feeble human race and is one of the cutest weapons in the Transformers armoury.

Every war has casualties and for once in this fantastical universe, compelling character development and heartfelt emotion aren’t among the fallen.

RATING: 7/10