Given our insatiable appetite for true crime content, it’s surprising that the story of Charles Sobhraj isn’t already mythologised in pop culture alongside the likes of Charles Manson and Ted Bundy. Better known as the Serpent – a nod to his reputation for slithering away from capture – Sobhraj first gained notoriety in the mid-70s for drugging, robbing and murdering a number of young western travellers who were making their way along South East Asia’s hippie trail.

Produced in collaboration with Netflix, the BBC’s new eight-part series delving into the crimes of the Serpent has been praised as much for its disturbing depiction of Sobhraj and his lover/accomplice Marie-Andrée Leclerc (played by Tahar Rahim and Jenna Coleman respectively), as its broader commentary on how the 1960s hippie dream turned sour.

The seed of the idea for the series was first planted over two decades ago, when director Tom Shankland was travelling across Asia. “I was in Nepal, in a Himalayan village, aged about 19, when I first heard about Charles Sobhraj,” he says. “There were a few of us huddled in the dark, telling traveller tales, buzzing after a day of trekking through the most beautiful mountains in the world, waxing lyrical about the amazing people and places you see on the road, when someone said, ‘You can’t trust everyone you meet’. She went on to talk about a guy – possibly a Frenchman – and his girlfriend.”

While at the time Shankland assumed it was little more than a hippie trail bogeyman tale, the story popped back into his head several years ago when he was thinking about potential ideas to develop into a feature film. After a bit of Googling, he came across a book originally published in the 80s called The Life and Crimes of Charles Sobhraj, and was swiftly sucked back into the murky world of the Serpent.