Replicas — young, gorgeous and apparently indestructible cyborgs - have become the acceptable face of humanity in Bruce Willis’s latest sci-fi blockbuster.

Spotty, schlubby citizens ‘‘operate’’ these creatures from the safety of their own bedrooms (men are able to take on female selves and white codgers can reinvent themselves as black). Then, one day, the murder of a surrogate changes everything. Enter Brucie, sporting a full head of hair.

As grieving FBI agent Greer, Willis has a blonde fringe, baby-smooth skin and a breakfast-news smile. His real self, we discover, resembles a bald, greying, pissed-off garden gnome, ie Brucie as he has looked for the past 20 years.

Willis loves making fun of his leading-man image but you can’t help feeling director Jonathan ‘‘Terminator 3’’ Mostow has gone for the obvious joke. If only he had cast Michael Douglas or even Nicolas Cage, two ageing icons who carefully protect their personas, in the lead; to see them stripped of their warm-tone wigs and make-up, to peer beneath their scented skin. Now that would have been a shock to the system.

Much about the plot, not to mention its action set pieces, feels same-old — conglomerates and robots versus ordinary people. And the editing is nuts. Intriguing scenes are brutally cut short (many of them involving Greer’s FBI partner, the underused Radha Mitchell) and pointless tableaux drag on. But the central conceit — that humans can’t stand the sight of each other — resonates.

Channel 4’s 10 Years Younger, for example, suggests that during the credit crunch employees have spent their redundancy money on nips and tucks to make themselves “fit” for the workplace.

Surrogates is an enjoyable parable, a candy-coloured reminder that while it may be liberating to have a healthy body, perfection — whether for men or women — is a gilded cage.