By Paul Taylor and Alastair Macdonald
BRUSSELS (Reuters) - The European Union is offering Britain a new "emergency brake" rule that could help curb immigration from other EU states in a reform package before a British referendum on EU membership, sources close to the negotiations told Reuters on Thursday.
The proposal would give any member state that could convince EU governments that its welfare system was under excessive strain a right to deny benefits to new workers arriving from other EU countries for up to four years. That has been a key demand of Prime Minister David Cameron and one which many EU leaders have said risks conflict with citizens' treaty rights.
Cameron will discuss the proposal in Brussels on Friday with European Commission President Jean-Claude Juncker, whose institution would have to initiate any such legislation, sources said. Cameron is keen to have measures adopted that can convince Britons to vote to stay in the EU, possibly as early as June.
If he and Juncker agree, then a broader, outline package of EU reforms could be approved by Cameron in a meeting on Sunday with European Council President Donald Tusk. Much of the rest of the package has already been broadly agreed, the sources said.
Tusk, who chairs EU summits, is expected to circulate written proposals on reform to the other 27 EU governments early next week with the aim of resolving remaining disagreements when EU leaders next meet in Brussels on Feb. 18-19.