As he strolled along the street in the Chinese city of Urumqi, trying his best to look like a tourist, Guan Guan’s heart was in his mouth. 

He knew this was not a place often visited by holidaymakers – and a camera hidden on his backpack was secretly filming the Communist regime’s internment camps.

The brave young man was on a covert mission: to expose to the world the hideous network of re-education camps, detention centres and prisons at the centre of Beijing’s brutal clampdown on Muslim minorities, especially the Uighurs, in Xinjiang province.