Mr Cameron said:
This is a landmark agreement that will save lives and ease the immense human suffering caused by armed conflict around the world.
It will reduce the number of illegal arms and make it harder for these to reach the hands of criminals and terrorists who are set on using them to destroy the lives of others.
We should be proud of the role Britain has played to secure this ambitious agreement, working with international partners to secure this momentous step that will make our world safer for all.