Three years ago, few could have predicted that Salman Khan – Bollywood’s somewhat incredible hulk, then mired in career controversy – would eventually devote himself to issuing humanitarian statements in film form. This curious turn into mid-career community service began with 2015’s summer mega-hit Bajrangi Bhaijaan, in which the star sought to build bridges between India and Pakistan; it continued through last year’s biopic Sultan, where an ageing action man pondered how best to use his muscle. In new release Tubelight, the charm offensive stutters: with its pitifully glib pleas for peace, this 1960s-set mushfest makes Culture Club’s low-barring The War Song sound as though it was written by AJP Taylor.

The unlikely source material is Little Boy, 2015’s Emily Watson/Kevin James farrago, although UK viewers may be haunted by lingering traces of a similarly titled Rolf Harris number. Khan’s pea-brained yet broad-shouldered Laxman gains the nickname Tubelight after fluorescent strip lighting reaches his mountaintop village: a dim bulb, he’s considered slow to spark into life. His younger sibling is Bharat (Sohail Khan), hale and heartier, and therefore among the first to be drafted when tensions escalate along the Indo-Chinese border. Thus are our boys torn asunder: wide-eyed Laxman left at home blinking and worrying, while Bharat endures dusty battle scenes, time in a POW camp, and a general sense of innocence being lost.

Some of this innocence could well do with getting lost. The sight of the now-fiftysomething Salman playing the teenage Laxman is unignorably ridiculous: with his tank top, slicked-down hair and worried grimaces, his flies forever undone by way of a vaguely disturbing running gag, the figure he most resembles is Ricky Gervais as Derek. Then again, Laxman’s entire journey feels both forced and familiar. As he overcomes local suspicions to befriend the young son of a Chinese refugee, Salman and director Kabir Khan appear to be directly replaying Bajrangi, albeit with a child performer who’d have fared better being left in their trailer to get on with their homework.

The spin here is that this is big-hearted Salman reaching out and making friends with that emergent Chinese audience who, as their considerable contributions to Dangal’s global box-office recently illustrated, are embracing Bollywood in their millions. Yet olive branches lose their symbolic worth when they come with a price tag attached. Bajrangi’s sentiment was to some degree sincere, which is why it left us – against our rational instincts – blubbering in the aisles; here, it’s thin syrup drizzled over a cold-eyed business proposition, one as calculated as any of those western blockbusters that have taken to shooting cutaways of Fan Bingbing in the hope of making off with a little extra yuan.

Flickers of a more warming experience persist. Despite a tinkly incidental score shamelessly plundering Baby Face for its leitmotif, the songs are someway stronger than the dialogue; the late Om Puri adds clout as a village elder, and Shah Rukh Khan enjoys a nimble cameo as a travelling magician. Yet everyone’s deferring to a producer-star whose saviour complex looms heavy over every frame. These past few years have seen Salman becoming smarter about his public persona – Laxman literally strives to move mountains to bring people together. But without the tears that might soften our vision, all Tubelight resembles is a rebranding process: somewhere between act of vanity and lamentable waste of energy.