EU leaders go into a make-or-break summit on Thursday facing difficult compromises to keep Britain in the bloc and wrangling with Europe's worst migrant crisis since World War II, AFP reports.

Prime Minister David Cameron's demand for key reforms in return for Britain's continued membership has exposed a rift over whether the EU's future is to move ever closer together or to ease ties, becoming a looser group of distinct sovereign nations.

Fail to get a deal and Cameron has said anything is possible, including Britain becoming the first country to leave the 28-nation bloc after an in-or-out referendum that could come as early as this summer.