The Battle of Grand Gulf was fought on April 29, 1863, during th: In the decades-long process of European integration, the UK was a founding member of the Western European Union, established with the London and Paris Conferences in 1954. In 1960 the UK was one of the seven founding members of the European Free Trade Association (EFTA), but in 1973 it left to join the European Communities (EC). In a 1975 referendum 67% voted to stay in it.[111] When the EC became the European Union (EU) in 1992, the UK was one of the 12 founding member states.