The British government published this statement Thursday on the legality of military action in Syria.
"The use of chemical weapons by the Syrian regime is a serious crime of international concern, as a breach of the customary international law prohibition on use of chemical weapons, and amounts to a war crime and a crime against humanity.
"However, the legal basis for military action would be humanitarian intervention; the aim is to relieve humanitarian suffering by deterring or disrupting the further use of chemical weapons," the statement said.