1973 enlargement of the European Communities

Denmark, Ireland and the United Kingdom (UK) acceded to the EC on 1 January 1973.

Gibraltar and Greenland also joined the EC as part of the United Kingdom and Denmark respectively, but the Danish Faroe Islands, the other British Overseas Territories and the Crown dependencies of the United Kingdom did not join the EC.

[1] In 1960 the European Free Trade Association (EFTA) was established and was formed by Austria, Denmark, Norway, Portugal, Sweden, Switzerland and the United Kingdom.

These countries were often referred to as the Outer Seven, as opposed to the Inner Six of the founding members of the European Community (EC).

On 31 July 1961 the United Kingdom,[3] Ireland[4] and Denmark[5] applied to join the EC.