How might the UK act over Syria?

David Cameron has said the alleged use of chemical weapons by the Syrian government is "morally indefensible" after he recalled Parliament to discuss responses to the crisis.

The prime minister said the world could "not stand idly by" in the face of the "massive use" of banned weapons.

As the UK and the US consider their next steps over the Syria crisis, the BBC's Caroline Wyatt reports on the possible military options, and what they might hope to achieve.