We call it human trafficking nowadays but really the slave trade is alive and well. Whether it is Chinese cockle pickers in Morecambe Bay, or African vegetable pickers in Andalucia, or Filipino building workers in Dubai, there are lot of unsavoury people ready to trade in human misery, nowhere more so than in the sex trade. The stories are grimly familiar; innocence recruited (often, extraordinarily, by other women), trust betrayed, rape, imprisonment and then the never-ending queue of men.

Of the several Fringe shows on the subject some, such as Fair Trade, by young writers Shelly Davenport and Anna Holbek and backed by Emma Thomson, are earnest and well meaning. But none of them could even begin to compete with the harrowing intensity of Roadkill, a site specific piece from Glasgow based companies Ankur and Pachamama, brilliantly directed by Cora Bissett. 

Starting with much the same set of facts, Bissett brings every kind of theatrical technique to bear on the nondescript Edinburgh flat where it takes place, animation, projection, light and sound, as well as three performances of blazing, at times even frightening, conviction .

It begins on the bus to the venue. A young  (13) Nigerian girl (Mercy Ojelade) in a plain white pinafore dress and her glamorous Auntie (Adura Onashile)  are among the passengers.  Irrepressibly  excited to be here,  the girl chatters all the way to the flat where there are such amenities as - joy! - running water, permanent electricity and her own room. 

As she innocently dances to a Beyonce video on the widescreen TV, a friend of her Auntie (a quietly malevolent John Kazek) appears and takes her next door to “show her some more DVDs”. The audience is left watching the TV screen where the images abruptly give way to an animation (by Marta Mackova) of three hooded figures tearing apart a little girl in a white pinafore. You hear her screams through the walls. And that’s  just the beginning.

What follows is as challenging a 90 minutes of performance as I have ever witnessed. The images of the endless parade of men’s sweating, pumping  faces, seem from the girl’s point of view, projected onto the ceiling, will linger long in the memory.

The overall impact is shattering.  The urge to sign up to every anti-trafficking campaign and charity you can find afterwards is irresistible. And the killer is that it is based on a true story, from Glasgow, whose resolution is still not secure. 

Roadkill is returning for another run via the Tron in Glasgow in the autumn.