LONDON—British Prime Minister David Cameron faces two months of difficult negotiations in his bid to alter European Union rules ahead of a planned referendum on Britain’s continued membership in the EU.
Substantive differences remain, but Cameron and other European leaders said after a grueling negotiating session in Brussels they would search for a compromise ahead of a February summit.
The British leader, who won re-election in May, is under pressure to win concessions from Europe before holding a national referendum on whether Britain should stay in the bloc. Many in his own Conservative Party question the value of remaining in the EU.





