"Why Businesses Fail to Detect Modern Slavery at Work," 11 September 2017

... Companies can increasingly trace where their products come from – but not the workers who produce them. According to the National Crime Agency, there could be tens of thousands of victims of modern slavery and human trafficking in the UK. The crime is is far more prevalent than law enforcement previously thought. And businesses have little hope of detecting modern slavery practices unless they adopt a new approach that focuses specifically on their labour supply chains. 

...[T]he key issue in tackling modern slavery is in understanding the labour supply chain. These are often unregulated networks through which forced or trafficked workers may be recruited, transported, and supplied to business by third party agents...

Leading UK companies are starting to wake up to the fact that their existing systems for detecting worker abuse simply are not fit for purpose for uncovering modern slavery. But, as new initiatives emerge, the critical factor determining their success will be whether they meaningfully address the labour supply chains that feed their business... [refers to Apple]