Are journalists still able to tell the truth to power? On March 16th 1968 US soldiers committed a war crime during the Vietnam war. More than 500 men, women and children were systematically slaughtered in the village of May Lai. The terrible truth was exposed thanks to the work of investigative journalist Seymour Hersh. HARDtalk's Stephen Sackur speaks to him about a lifetime of reporting that has been punctuated by scoops, prizes and plentiful confrontations with the powers that be.