President of the European Council - Herman van Rompuy
Created under the 2009 Lisbon Treaty, the position was created to give the EU "one voice" on the world stage. The first and current holder of the position is the former Prime Minister of Belgium, Herman van Rompuy. The President may serve for a maximum of two consecutive terms of two and a half years. With the European Council being made up of all heads of government of the EU member states, the position is theoretically the most senior in the union as the post-holder is nominated by the EU government leaders. Indeed when it was first discussed, senior politicians such as Tony Blair were touted as possible presidents, as someone who could stride the world as a figurehead for "Europe". However, so far the position has been more low-key than at one time planned. Although Mr Van Rompuy is the EU's representative at global gatherings, and formally opens and closes EU summits, he usually shares the platform with the President of the European Commission. Officially the President of the European Council is in charge of "strategy", whilst the Commission President deals with "implementation". But with the language of the Lisbon Treaty being vague, an increasing amount of rivalry is developing between the two leaders.
President of the European Commission - Jose Manuel Barroso
Until the Lisbon Treaty, this was the most senior position in the EU. Yet despite the introduction of a European Council President, it is still the Commission President who is seen as the "person in charge". The post has been held since 2004 by Jose Manuel Barroso, a former Prime Minister of Portugal and a key ally of George Bush and Tony Blair during the Iraq War. He is nominated by the European Council, and serves a five year term which may be renewed. Many Commission presidents have emerged as "compromise" candidates but have proceeded to become strong figures in their own right. The Commission President is in charge of the "nuts and bolts" day to day issues affecting the EU, such as the economic crisis, rather than the long-term strategic policies, although innovations such as the annual "State of the Union" address show that more of a strategic role may be developing. Officially he/she has no role in policy areas that are covered purely by the Council and not by the Commission, which mainly covers foreign affairs issues. The post has been described by political commentators as "power without prestige", unlike the European Council President which could be seen as "prestige without power". There is talk of combining the two positions at some stage in the future, creating a true "President of the EU".
President-in-Office of the Council - Enda Kenny
This position rotates every six months, and is held by the head of the government of the country holding the rotating presidency of the Council of Ministers, currently Ireland. Three consecutive presidencies - known as the trios - work together to co-ordinate medium term policies of the EU. The current trio, lasting until the middle of 2014, is made up of Ireland, Lithuania and Greece. Since the creation of the European Council President and EU High Representative, this position has become increasingly symbolic. The President in Office will usually address the European Parliament at the beginning and end of the country's presidency of the EU, but apart from that, most of the long term planning is out of their hands.
President of the European Parliament - Martin Schulz
Similar in many ways to the Speaker of the House of Commons, the President of the European Parliament chairs the key debates of the plenary session of MEPs. Presidents serve a term of two and a half years, meaning there are two presidents during each five year European Parliament term. As well as chairing debates, the president - currently the German social democrat Martin Schulz - chairs the parliament's Bureau, which is responsible for its internal budgetary and administrative issues. He or she will also represent the European Parliament in all external matters, such as speaking at summits of the European Council. The president will also chair the conciliation committees that seek to reach agreement between the Parliament and the Council of Ministers in legislative matters. He or she will also give the final sign off to legislative acts and - most importantly - the EU budget. Finally, in EU protocol, the Parliament president is senior to the Commission or European Council president, meaning he or she will be the first to receive foreign dignitaries.
EU High Representative for Foreign Affairs - Catherine Ashton
Often described by some in the media as the EU's "foreign minister", the position of EU High Representative for Foreign Affairs and Security Policy was created by the 1997 Amsterdam Treaty and was strengthened by the 2009 Lisbon Treaty. The post is currently held by former leader of the House of Lords, Labour's Baroness Ashton. The position co-ordinates all day to day EU foreign affairs issues, and is the first head of the European External Action Service. He or she is also by default a member of the European Council and the senior vice-president of the European Commission. The High Representative is appointed by the heads of government of EU member states, but is then subject to a vote of approval from the European Parliament. He or she co-ordinates all aspects of the EU's Common Foreign and Security Policy (CFSP), and its Common Security and Defence Policy (CSDP).
President of the European Central Bank: Co-ordinates monetary policy in the eurozone, currently held by Mario Draghi from the Bank of Italy. The bank was set up in 1998 and has its headquarters in the German financial city of Frankfurt.
President of the Eurogroup: Chairs meetings of the finance ministers of eurozone countries, and looks after the "politics" rather than the "economics" of the single currency. Post currently held by Jeroen Dijsselbloem, the finance minister of Netherlands.
President of the European Court of Justice: Vassilios Skouris, former interior minister of Greece. The court is the highest body for dealing with the application of EU law. It is based in Luxembourg and is composed of one judge from each member state. Mr Skouris has been the chief judge since 2003, having been a member of the court since 1999.
President of the European Court of Auditors: Vitor Manuel da Silva Caldeira. The court, made up of one member from each EU state, was created in 1975 and audits the accounts of the EU institutions. Mr Caldeira - who presents an annual report of the court to the European Parliament - has chaired the court since 2007.
European Ombudsman: Nikiforos Diamandouros. The position was established by the Maastricht Treaty and investigates allegations of maladministration by EU institutions. Mr Diamondouros, who was appointed by MEPs, has been in the job since 2003.