The vote was called by David Cameron after he won last year's general election.
Prime Minister David Cameron said progress had been made in Britain's renegotiation of relations with the EU, after talks in Brussels on Friday, but it was "not enough".
"We have made progress today; it's not enough," he told Sky News television after talks with European Commission chief Jean-Claude Juncker.
"There is now a proposal on the table, it is not good enough, it needs more work."
Cameron met Juncker to discuss a "migration brake" that would meet his key demand -- a four-year limit before EU workers in Britain can claim certain welfare payments.
A referendum on whether Britain should leave the EU is expected to be held this year and must take place before the end of 2017.
The vote was called by Cameron after he won last year's general election.
Opinion polls currently suggest that Britons would narrowly vote to leave the EU.
Cameron is set to hold further talks with EU president Donald Tusk in London Sunday.
Tusk is expected to publish details of a proposed reform deal to try and keep Britain in the EU next week.
The negotiations to prevent a so-called "Brexit" from the 28-nation EU come amid a series of crises for the bloc including the biggest influx of migrants and refugees to Europe since World War II.
"We have made progress today; it's not enough," he told Sky News television after talks with European Commission chief Jean-Claude Juncker.
"There is now a proposal on the table, it is not good enough, it needs more work."
Cameron met Juncker to discuss a "migration brake" that would meet his key demand -- a four-year limit before EU workers in Britain can claim certain welfare payments.
A referendum on whether Britain should leave the EU is expected to be held this year and must take place before the end of 2017.
The vote was called by Cameron after he won last year's general election.
Opinion polls currently suggest that Britons would narrowly vote to leave the EU.
Cameron is set to hold further talks with EU president Donald Tusk in London Sunday.
Tusk is expected to publish details of a proposed reform deal to try and keep Britain in the EU next week.
The negotiations to prevent a so-called "Brexit" from the 28-nation EU come amid a series of crises for the bloc including the biggest influx of migrants and refugees to Europe since World War II.
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