British Prime Minister David Cameron delivers his EU membership speech at Chatham House on November 10, 2015, where he outlined his proposed plan for changes to Britain's EU membership. (AFP)
David Cameron's EU renegotiation demands for curbs on migrant benefits are "highly problematic", the European Commission said today after the British prime minister sent his objectives to Brussels.
"Prima facie, we see a number of elements which appear to be feasible like finding ways to increase the role of national parliaments, some issues which are difficult like ever-closer union and the relation between euro ins and outs," Commission spokesman Margaritis Schinas said.
"And 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," he added.
"The Commission considers the prime minister's letter as the beginning not the end of the negotiations. And as President (Jean-Claude) Juncker has repeatedly said, we stand ready to work for a fair deal with Britain that is also fair for all the other member states."
The British premier spoke to Juncker by telephone today, Schinas said.
Cameron sent a letter to EU President Donald Tusk today setting out his demands for guarantees for non-eurozone countries, greater competitiveness, an exclusion for Britain from "ever closer union" and curbs on some benefits for EU migrants.
Tusk said he would start talks with other EU nations next week.
"With David Cameron's letter, negotiations on #UKinEU can now begin," Tusk tweeted. "Next week, I will launch bilateral consultations with member states as well as EP (European Parliament) on topics to be addressed."
British finance minister George Osborne, who was holding talks in Brussels today with Juncker and Eurogroup chief Jeroen Dijsselbloem, insisted that London could get the reforms it wanted.
"Today Britain's formal renegotiation has begun. We are seeking changes and reforms so that Britain can remain in the European Union," Osborne, who is Cameron's closest political ally, told reporters.
"We're going to sit round the table and the negotiations are going to start and I think we've got a real good chance now of achieving the reform that we all want to see."
But EU sources warned of trouble ahead.
"At some point they (the British) will have to climb down their tree," one source told AFP.