Since the end of apartheid, almost 20 years ago, South Africa's Constitution has become one of the most admired in the world - progressive, transformative, guaranteeing equality and human rights. But despite the great strides the country has made, the reality is failing to live up to the promise. The legal system, which guarantees the Constitution, has itself come under fire from within the government, the opposition, and from some human rights groups. Gavin Esler speaks to South Africa's Chief Justice, Mogoeng Mogoeng.