Sex work is legal in Bangladesh. So is child marriage. Now in an exclusive investigation, The Telegraph can reveal the two have become intrinsically linked

There’s a circular bruise blossoming on the right hand side of 19-year-old Rupa Begum’s cheek, and she’s working hard to cover it. Gently, she smears pale concealer over her face with her fingertips and blends it into the skin.

She checks her reflection in a small turquoise mirror, and breaks into a smile. “Now nobody can tell anything happened,” she says, sitting back on her faded floral bedspread. “When the next customer comes, he doesn’t want to see what the last one did to me.”

It’s 9.30am on a Tuesday morning, and outside Rupa’s windowless bedroom, the Bangladeshi brothel corridors are already thick with the smell of spices and sweat.

Men of all ages in stained polo-shirts and traditionally knotted ‘lunghi’ elbow each other out the way as they make their way through the maze of brightly-painted concrete alleyways and narrow streets to find their chosen girl and hand over 200 taka [£1.75] for ten minutes of sexual activity before work.