On 8 December at a summit in London Britain’s prime minister David Cameron told delegates from 50 countries and 26 tech firms that online child exploitation “existed on an almost industrial scale" around the world. He announced an “unprecedented package of global action” to hunt paedophiles who use the internet. And just weeks before that a committee of British politicians revealed their belief that the intelligence services could have stopped a May 2013 terror attack in London if Facebook had alerted the authorities to an online exchange between one of the attackers and another extremist. In this edition of The Inquiry we ask: Can the internet be policed? Presenter: Jo Fidgen (Photo: Big Data. Credit: Carlos Amarillo)