The European Union is seeking a fair deal that will provide a way out of a complicated question over the future of Britain's membership in the bloc, European Commission president Jean-Claude Juncker said on 17 December.

British Prime Minister David Cameron will make a bid to renegotiate the terms of Britain's membership of the bloc at a summit in Brussels later in the day, ahead of a referendum he has promised by the end of 2017 that will decide whether the United Kingdom will remain a member of the bloc.

"We want a fair deal with Britain. This fair deal with Britain has to be a fair deal for the other 27 [member countries] too, so we are open-minded. We are engaging in this dialogue which will be a negotiation with Britain in an open-minded way. I don't want the British to leave, and I don't want to blame the British. They have their points, we have our points, and as reasonable people, we will find a way out of the complicated situation we are in," Juncker told a briefing in Brussels.

Cameron faces an uphill battle to secure agreement on curbing welfare payments to EU migrants to try to reduce immigration in talks which the EU's main negotiator, Donald Tusk, said could not "escape a serious debate with no taboos." Juncker said he was convinced EU leaders would find a solution to "that highly complicated question" of benefits, which Cameron said he must secure to ease concerns among British voters over immigration.

Tusk added: "We'll enter the concrete and vital phase of negotiations with our British colleagues. The Commission is ready to look for other options than the single one proposed by the British prime minister and I'm quite convinced that we will find a solution to that highly complicated question."

Cameron has won encouragement from German Chancellor Angela Merkel, Europe's main powerbroker, and other leaders who want to keep Britain in the bloc. He has also got sympathy for his calls for greater competition in the EU, more sovereignty for Britain and safeguards for the City of London financial centre.

But his proposal to make immigrants from the other 27 EU states wait four years before claiming "in-work" benefits in Britain – payments to people in lower paid jobs to make work more attractive – has been roundly criticised, especially in eastern Europe, for breaking EU law banning discrimination.