Stephen Sackur speaks to Dr Fatih Birol, executive director of the International Energy Agency and one of the world's most influential observers of the global energy market. The price of oil has more than halved over the past two years. That's great news if you're an oil consumer but it's alarming if your priority is to wean the world’s economy off carbon emitting fossil fuels. Does cheap oil make decarbonising the world economy even more difficult?

(Photo: Dr Fatih Birol in the Hardtalk studio)