Hilary Andersson explains how Panorama uncovered evidence of China sending military equipment to Sudan
Sudan's president has been accused of genocide, crimes against humanity and war crimes in Darfur by the prosecutor of the International Criminal Court.
Luis Moreno-Ocampo told judges at The Hague that Omar al-Bashir bore criminal responsibility for alleged atrocities committed over the past five years.
The move comes as, after months of investigating China's covert arms trade, Panorama provides the first evidence of how China is arming Sudan's killers.
Sudan, with its vast oil reserves, sells most of its oil to Beijing.
The Panorama team follows a trail through Chad and Darfur, tracking down Chinese military trucks, one of which with a mounted Chinese gun, had recently been used against civilians, according to local witnesses.
Panorama also establishes that China is currently training fighter pilots who fly Chinese built and maintained fighter jets.
These have been used in recent attacks in a conflict which has now cost an estimated 300,000 lives.
Next month's Beijing summer games have been dubbed the 'Genocide Olympics' by Hollywood campaigners.
They accuse China of supplying the Sudanese government with arms to enable it to wage a campaign of violence in Darfur.
Stephen Spielberg recently cut his ties with the Olympics over the issue.
Beijing and Khartoum have long had strong political, economic and military ties.
Because of this strong relationship, Chinese leaders have traditionally resisted international pressure to use their clout to bring peace to Darfur, where there is conflict between government-backed militias and rebels.
Beijing has even used its veto at the UN Security Council - to block moves to impose sanctions on Sudan if it fails to stop the fighting in the troubled region.
Panorama: China's Secret War will be on BBC One at 8.30pm on Monday 14 July 2008.