David Cameron says a deal struck with EU leaders will give the UK "special status" and he will campaign with his "heart and soul" to stay in the union.
The agreement, reached late on Friday after two days of talks in Brussels, gives the UK power to limit some EU migrants' benefits.
It also includes a treaty change so the UK is not bound to "ever closer union" with other EU member states, he said.
The Eurosceptics will dismiss this deal, but it's certain that they would have dismissed whatever deal Cameron brought back. Nothing except exit would be good enough for them. The question is whether, in the event of Britain voting to leave the EU, they would be able to get a decent exit deal from the EU leaders. It seems pretty doubtful.
David Cameron has once again shown that he is one of the greatest political figures of our age.