Jonathan Head has spent six months investigating the trafficking of humans in Thailand. The plight of thousands of migrants stranded on boats in the Andaman Sea has drawn global attention to a sinister trade in people, which has thrived in south east Asia.
The decision by Thailand this month to finally move against people smugglers left hundreds of migrants drifting on boats out at sea.
For years, though, Thailand has been accused of ignoring the trade centred inside its borders. Those affected are mostly Rohingya migrants from Myanmar, and increasingly, impoverished Bangladeshis, all seeking jobs in Malaysia. The main route has been through Thailand - where ruthless traffickers hold them until their families pay for their release.