Japan 'underestimated' tsunami hazard

A UN nuclear safety team on a visit to the country has said that Japan underestimated the risk of a tsunami hitting a nuclear power plant.

However, the response to the nuclear disaster which followed the 11 March quake and tsunami was "exemplary".

The International Atomic Energy Agency (IAEA) team also said a "hardened" emergency response centre was needed.

The BBC's Roland Buerk outlined the UN's findings.