At night, while travelling for hours along Xinjiang's desert highways, the unmarked cars that had been following us from the moment we arrived would tailgate us at speed, driving dangerously close with their headlights on full beam. Their occupants - who never identified themselves - forced us to leave one city by chasing us out of restaurants and shops, ordering the owners not to serve us.
The report we produced, despite these difficulties, contained new evidence - much of it based on China's own policy documents - that thousands of Uighurs and other minorities are being forced to pick cotton in a region responsible for a fifth of the world's crop.
