The Parliament of the Presidency traditionally performs certain functions while the Member State holds its Presidency of the Council. After the Treaty of Lisbon designated a weightier role to national Parliaments, the significance of the parliamentary dimension of the Presidency has also greatly increased. Back in 2004, the Conference of Speakers of the EU Parliaments held in The Hague approved the Guidelines for Inter-parliamentary Cooperation in the European Union, which were subsequently updated at the Conference of Speakers of the EU Parliaments held in Lisbon in June 2008. The Guidelines set the main forms of the EU parliamentary cooperation:

-          Conference of Speakers of the EU Parliaments;

-          Conference of Parliamentary Committees for Union Affairs (COSAC);

-          Joint Parliamentary Meetings;

-          Inter-Parliamentary Committee Meetings;

-          Meetings of Secretaries General (Heads of Administration) of the EU Parliaments.

The Treaty of Lisbon has introduced a number of novelties associated with the Presidency of the Council of the EU. One of them is official grouping of Presidencies into Trios. Prior to Lisbon, Trio Presidencies served as an unofficial form of cooperation. Trio Presidency lasts for 1,5 years. This novelty is important in solving the tasks of the parliamentary dimension of the Presidency of the Council. Parliamentary events and their topics have to be coordinated not only with the Presidency programme but also with the other parliaments of the Trio. Lithuania will assume the Presidency of the Council of the EU in the second half of 2013 together with Ireland (the first half of 2013) and Greece (the first half of 2014). With a view to ensuring smooth cooperation among the Trio Presidency Parliaments, the Speaker of the Seimas of the Republic of Lithuania, Mrs Irena Degutienė, Chairman of the House of Representatives of Ireland, Mr Seán Barrett, Deputy Chairman of the Senate of Ireland, Mr Denis O‘Donovan, and Secretary-General of the Hellenic Parliament, Mr Athanassios Papaioannou (on behalf of the Speaker of the Hellenic Parliament, Mr Philippos Petsalnikos) signed the Declaration of Cooperation among the Houses of the Parliaments of Ireland, Lithuania and Greece in support of the preparation and fulfilment of the parliamentary dimension of the Presidencies of these three European Union Member States for the period 1 January 2013 – 30 June 2014.

The Declaration was signed at the Conference of Speakers of the EU Parliaments in Warsaw.