Wikipedia says Britian subsequently applied to join the European Economic Community  (EEC) in 1963 and 1967 and failed.  On January 1, 1973 UK finally succeeded to join the EEC but again challenged by a referendum on 1975 asking votes for yes or no on the question: “Do you think the UK should stay in the European Community (Common Market)?”. So if you think the recent ‘Brexit’ came all on a sudden, you are wrong. In 1975 ‘yes’ won with 67.2% vote, but yesterday it’s the ‘no’ who won when the question was for the whole European Union. Here is a map from NY Times showing the result.