In his speech at the United Nations General Assembly, the Iranian President Mahmoud Ahmadinejad has launched a fierce attack on Western policies and values, prompting delegations from 36 countries to walk out. Mr Ahmadinejad said "arrogant powers" threatened anyone who questioned the Holocaust and the 9/11 attacks.

"By using their imperialistic media network, which is under the influence of colonialism, they threaten anyone with sanctions and military action - anyone who questions the Holocaust and the 9/11 event."

Well, the British Prime Minister David Cameron has told the UN that events in the Arab world show that the organisation needs new ways of working to spread democracy. He said the Arab Spring presented a massive opportunity to spread peace and security.

"We have a responsibility to stand up against regimes that persecute their people. We need to see reform in Yemen, and above all, on Syria, it is time for the members of the Security Council to act. We must now adopt a credible resolution threatening tough sanctions."

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Stock markets around the world have fallen sharply after warnings about the economic outlook. The leading European markets all fell about 5% with London's FTSE 100 index seeing its biggest one-day fall since March 2009. Shares in New York were down nearly 4% at one point. Christine Lagarde, the head of the International Monetary Fund, called for more political leadership. She said the stakes were high in the eurozone debt crisis.