Enlargement is the process by which new member states join the EU.
The seeds of what is today’s European Union, were sown in 1957, when six founding member states signed the Treaty of Rome, which led to the creation of the European Economic Community (EEC).
Since 1957 the EEC has become the EU, and has enlarged six times, and now comprises 27 member states.
The prospect of EU membership has been, and remains, a powerful incentive to change. It has been an important force behind the very fundamental political and economic transformation seen in the countries of Central and Eastern Europe that joined the EU in 2004 and 2007.
It is exerting the same powerful influence on Turkey, Croatia and Macedonia, who are all candidates for EU membership.
There are also a number of 'potential' candidate countries, often referred to as the Western Balkan countries: Bosnia and Herzegovina, Albania, Montenegro, Serbia, and Kosovo(Under UN Security Council Resolution 1244/99).
The EU has consistently voiced its committment to eventual EU membership for these Western Balkan countries.
Iceland also submitted an application for EU membership on 23 July 2009.
Further enlargement of the EU benefits existing EU Member states. With each previous enlargement the EU has emerged stronger, more confident and more capable of acting on the world stage.
Importantly, an enlarged EU will help us tackle threats which cannot be confined by geographical borders, from climate change and organised crime, to the fight against terrorism. Close cooperation with our neighbours is a major force for dealing with such challenges.
Further enlargement enhances economic dynamism in the EU by expanding the internal market and creating a level playing field for business. It will improve Britain’s ability to meet the challenges and opportunities presented by globalisation.
An enlarged EU also invites wider and richer cultural discussion and creativity. An exciting example of this is ‘Enlarge your Vision’ - the 2010 Young Journalist Award launched by the EC’s directorate general for enlargement. This is a competition for young journalists from across Europe, offering them the opportunity to showcase their work and to exchange opinions with the European Commission, on some of the key issues emerging from the enlargement project.
The process through which new member states join the European Union is known as Accession.
Croatia is a candidate for membership of the European Union. Read more about the UK's support for Croatian EU accession.
Turkey is a candidate for membership of the European Union. Read more here about Turkey's progress in the EU accession process.
Progress towards membership of the European Union will help to promote democracy, stability and economic development in the Western Balkans.