Cameron: 'We helped avert a bloody massacre in Benghazi'

David Cameron has told MPs action in Libya has already helped avert a "bloody massacre" in Benghazi, as he opened a debate on the military action ahead of a vote this evening.

Air strikes by allied forces began this weekend, after the UN Security Council backed a no-fly zone over Libya and "all necessary measures" to protect civilians short of an occupation.

The UN decision follows weeks of violence in Libya as protestors demand autocratic ruler Colonel Muammar Gaddafi steps down, despite attempts by Gaddafi loyalists to crush the rebellion by force.