In 1983 an Islamic fundamentalist carried out a hugely successful suicide mission, almost completely wiping out the CIA operation at the US Embassy in Beirut. Six months later, another suicide bomber killed 241 US Marines after receiving the blessingof Sheikh Fadlallah, spiritual leader of Hezbollah. Between them they had effectively driven the US out of Lebanon. As a result, Colonel Bill Cowan was sent to Beirut on an undercover mission, charged with devising ways of retaliating. In tonight's film he returns there, and reveals the details of that mission, targeted at Fadlallah. Meanwhile, in the White House, President Reagan was promising that there would be no deals with the terrorists. The reality was precisely the opposite of the rhetoric. Peter Taylor presents the fourth in the series investigating state response to terrorism.