British Prime Minister David Cameron has urged the leaders of European Union member states to reach a “credible deal” that will allow his country to remain part of the EU. At a summit in Brussels on Thursday, he said the issue of Britain’s place in EU had been allowed to fester for too long. He has been seeking changes to the United Kingdom-EU relationship for three years, for which talks have been held. Once a deal on the same is settled, he said he will back a “yes” vote in a referendum in June on continued membership, AFP reported.

The British prime minister did not rule out the possibility of his country leaving the EU if members do not come to an agreement. The revisions Cameron has sought include restricting welfare benefits available to immigrants to curb immigration, which he says has strained their social services budget. He also wants safeguards for countries like Britain that do not use the Euro currency, greater competitiveness among member states and the choice to opt out of closer EU integration.

While Britain wants to limit benefits for new migrants for seven years, according to the Associated Press, a four-year limit was offered in Brussels. However, Poland and other east European countries that have thousands of citizens in Britain opposed the restriction, claiming it will discriminate against them and weaken the EU’s principle of freedom of movement. Also, Cameron had the support of German Chancellor Angela Merkel, who said Berlin shared his concerns, but French President Francois Hollande expressed apprehension at the protections for non-eurozone countries.