Main Treaty amendments since the UK joined the EEC

Since the UK joined the European Economic Community in 1973 several major Treaty amendments have changed the EU’s structure, decision-making procedures and the policy areas in which the EC/EU can act.

This Note outlines the key changes in these areas since the Single European Act in 1986 – the first major Treaty change after the UK joined the EEC. It looks at the following:

- Single European Act
- Treaty on European Union (Maastricht)
- Treaty of Amsterdam
- Treaty of Nice
- Treaty of Lisbon