Overview: Engineers are racing to cool down a third reactor at a quake-stricken Japanese nuclear plant, after a second blast rocked the facility. Tonight, we ask how severe the nuclear emergency is, and what the implications are for the nuclear sector and energy mix worldwide. We are also examining the impact the earthquake and tsunami is likely to have on the Japanese economy and in turn on the worldwide recovery. Plus, with the pace of events on the ground in Libya outstripping any co-ordinated international response we ask whether this is a tipping point for the diplomatic community. And we have a report from Jeremy Bowen, filmed during his recent days in Tripoli, in which he draws his own conclusions about the uprising and subsequent civil war.