Stephen Sackur speaks to veteran Palestinian negotiator and secretary general of the PLO Saeb Erekat. Why are so many mostly young Palestinians intent on killing Israeli Jews with whatever weapons they can lay their hands on? The Israeli government blames the surge in violence on hate-fuelled incitement sanctioned by the Palestinian authorities. The Palestinians say it is a response to the intolerable conditions of occupation. Is a new wave of extremism sweeping the West Bank and Gaza?