STUART RUSSELL - Professor of Computer Science, University of California, Berkeley

What is the most serious existential threat facing humanity? Artificial Intelligence, warned the physicist Stephen Hawking, could spell the end of the human race. Stephen Sackur interviews Stuart Russell, a globally-renowned computer scientist and sometime adviser to the UK Government and the UN. Right now, AI is being developed as a tool to enhance human capability; is it fanciful to imagine the machines taking over?