- 28 members (500+mn people)
- 1973: UK, Ireland, Denmark
- 1981: Spain, Greece
- 1986: Portugal
- 1995: Austria, Finland, Sweden
- members from 2000s: Estonia, Latvia, Lithuania, Hungary, Poland etc
- Requirements for members
a. Must be 'European' but no consensus on definition.
b. Copenhagen Criteria 1993, democratic etc.
c. Got to accept all existing treaties.
d. Must have a market economy, and ability to cope competitive pressure of market forces within EU.
e. Must be committed to maintaining momentum of political, monetary and economic integration.