The career of Bollywood megastar Sanjay Dutt has been the rockiest of rides. Born to Nargis, iconic figurehead of 1957’s Mother India, Dutt’s initial breakthrough was stymied by drink, drugs and womanising, and subsequent comebacks separated by stretches of prison time. His air of disrepute bolstered 2006’s terrific comedy Lage Raho Munna Bhai, where Dutt played a heavy nagged towards virtue by Gandhi’s ghost: the gags there had the ring of hard truth. That film’s director Rajkumar Hirani now brings us a decidedly soft and authorised-looking biopic featuring boyish pin-up Ranbir Kapoor as the roguish colossus, which to British eyes seems like recruiting, say, Men’s Hour lynchpin Tim Samuels to play Ray Winstone.

In actuality, Kapoor proves a lightweight film’s strongest suit: he’s accumulated enough muscle mass, the bags under the eyes that speak to late-night licentiousness, even a measure of Dutt’s bad-boy swagger. Everything else about this hagiography intends to make the character look good. Sanju opens with Dutt’s third wife Manyata (Dia Mirza) persuading an initially sceptical journalist (Anushka Sharma) to tell her suicidal hubby’s side of the story, and that’s exactly what this script does, generating nigh-on three hours of self-justification. The drugs were the actor’s way of escaping his father’s control and his mother’s decline. The women? He was irresistible and broken-hearted. The guns? There for protection. The infamy? Blame the press.

There’s a certain old-school comic nous about an early mix-up involving women and whisky (“I was enjoying an 18-year-old on the terrace…”), but it’s otherwise sad to see an irreverent talent like Hirani tidying up generally unruly legend, and trying to reframe a lot of grimly male misbehaviour as simple misunderstanding. At a moment when film industries worldwide are having an overdue rethink of their relationship to star privilege, an ambiguous life such as this might have offered up a cautionary tale, or at the very least some learning curve. What we get instead is a patchwork of feeble evasions and celebratory elaborations.