The enormous challenges facing the EU free movement of people in the face of internal inequalities and external instability, means innovative thinking is necessary to reform the principle in light of changes in the assumptions about the conditions underpinning it.
Charles took to the radio in an interview with Monocle debating what next for migration policy. Also featured in the programme were the Polish ambassador to the UK, Witold Sobkow, and the director of Oxford's Migration Observatory, Madeleine Sumption.
Click here to hear hthe interview.