At one stage in the 1980s Margaret Thatcher, the former British Prime Minister (also known as the Iron Lady), called the European Parliament a Mickey Mouse parliament. 

The European Parliament has developed considerably in terms of form and influence since its tentative start in 1952. Back in 1952, when the European Parliament was called the Assembly and only had members who were also members of the national parliaments of the Member States, there was only talk of a democratic assembly with an advisory function. The first steps towards giving the European Parliament real influence were taken in 1975 when Parliament was given the power to amend the Council’s draft budget or simply to reject it. 

The next major step towards greater influence was taken in 1986 when, with the adoption of the Treaty amendment known as the Single European Act, the European Parliament participated in the general legislative process through the procedure called the cooperation procedure which was used in particular for legislation concerning the Single Market. Another important change that was introduced enabled the European Parliament to approve accession treaties with new Member States, which means that Parliament now approves the agreements that the Council enters into with the new Member States concerning their admission to the EU.

The biggest extension to date of the influence of the European Parliament took place when the Maastricht Treaty entered into force on 1 November 1993. The Maastricht Treaty made the European Parliament a co-legislator with the Council in a number of policy areas. The key procedure which gives Parliament this major influence is the codecision procedure and, as the name implies, the key feature of the procedure is that an EU legal act cannot be adopted without the Council and the European Parliament agreeing on its adoption. 

The new Constitutional Treaty also increases Parliament’s influence substantially. Among other things, Parliament will in principle become an equal co-legislator with the Council when the codecision procedure becomes the ordinary legislative procedure, the Council and Parliament will be put on an equal footing in the budgetary procedure and Parliament will elect the President of the Commission.