Internal Market
The term "internal market" was introduced in 1987 by the Single European Act (SEA) to indicate the removal of all obstacles to the free movement of goods, services, capital and persons. It also refers to a market with a high degree of harmonisation of laws governing trade rules, specifications of goods, etc.
Yet the treaties still refer to either the "common market", in Art. 94 TEC where laws can only be put under harmonisation with unanimity, or the "internal market" in Art. 95 TEC, where laws can be harmonised by qualified majority in the Council with co-decision in the EU Parliament.
The internal market can best be defined as a more uniform and thorough-going common market.
Notes
Some say that the term Internal Market was only used as a pretext for introducing qualified majority voting in this area since the distinction between "internal" and "common" market is difficult.Future
The Lisbon Treaty proposes the "internal market" to become a shared competence (Art. 4 TFEU). EU law would therefore suppress member states' existing legislation and right to legislate in these areas. When it comes to competion rules for the functioning of the internal market this is a exclusive competence of the Union (Art. 3 TFEU) and therefore Member States may not legislate.
Links
http://www.europa.eu.int/pol/singl/index_en.htm
