It is a sumptuously sleazy-sentimental melodrama about the Mumbai underworld, directed with panache by Sanjay Leela Bhansali, the titan of Bollywood filmmaking who received a Bafta nomination for his enormous epic Devdas two decades after.

It is an adaptation of a story from Hussain Zaidi’s true-crime bestseller Mafia Queens of Mumbai: Gangubai Kathiawadi, who was tricked and trafficked into prostitution in Mumbai’s Kamathipura red-light district in the 1960s. However, rose to become an underworld madam involved in drugs and violent crime through her survivor’s ruthlessness and astute cultivation of political connections.

She subsequently parlayed her gangland status into a media persona, lobbying for sex workers’ rights and even visiting India’s first Prime Minister, Nehru, to discuss them. Alia Bhatt stars as Gangubai, an innocent rural girl who dreams of cinematic glory and is seduced by her nasty smoothie lover.

Then she is imprisoned, raped, and severely brutalized in the brothel. Still, she becomes a kind of unofficial union representative for the other women, pleading for justice to a local city politician: Karim Lala (Ajay Devgn), in exchange for whom she extends the brothel’s onsite liquor license.

Thus starts her upward journey, which includes a political struggle with a competitor, portrayed by Vijay Raaz’s trans madam Raziabai. This fictionalized version omits any violence in which Gangubai was allegedly involved and replaced drugs with alcohol sold on the premises.

The film loses some enthusiasm when Gangubai finally transforms from a mafia queen into a revered Mother India figure, blessed by smiling sex workers throughout Mumbai. However, this film has tremendous vigor, daring, and some impressive fantasy-musical setpieces.

Indeed, it is the streak of schmaltz amongst the gore that imbues the narrative with its ludicrous fire. This film has an endearingly arrogant air, a brashness and recklessness that contrasts with its mawkishness: it has a killer narrative instinct.

Gangubai Kathiawadi is slated to unveil in theatres on 25 February.