Kaing Guek Eav - better known as Duch - was head of a notorious prison camp and is accused of presiding over the murder and torture of at least 15,000 inmates.

The trial is the result of a decade of painstaking and often ill-tempered negotiations, a BBC correspondent says.

People queued for hours to attend the hearing and see the ex-prison chief.

For the survivors, the opening day of the hearing offered the first opportunity to see a leading figure in the Khmer Rouge face justice.