Cameron said the European Union must agree to "irreversible changes" — and limit freedom of movement by allowing the U.K. to restrict benefits for migrants from other member states — as part of the broad reform package he seeks. Cameron outlined his demands Tuesday in a speech in London and a letter to European Council President Donald Tusk, marking the formal opening of what is expected to be a difficult campaign for concessions from other European leaders. Cameron told an audience at the Chatham House think-tank that Britain wants change in four areas, including protection for countries such as Britain that don't use the euro single currency, less red tape and greater power for national parliaments to opt out of rules made by the Brussels-based EU. "Some things which are highly problematic as they touch upon the fundamental freedoms of our internal market, direct discrimination between EU citizens clearly falls into this last category," Schinas said.