Should governments spend more money? 'Modern monetary theory' or MMT is gaining traction, particularly in the US. It says governments should worry less about balancing the books. Its detractors call it the 'magic money tree'. Manuela Saragosa speaks to hedge fund founder Warren Mosler - the man who first proposed MMT - and economist Frances Coppola about the criticisms facing the theory.

Producer: Laurence Knight

(Photo: a magic money tree, Credit: Getty Images)