Anglo-Irish Agreement signed by Margaret Thatcher, British Prime Minister, and Garret FitzGerald, the Irish Taoiseach (Prime Minister), on 15 November 1985 at Hillsborough Castle, County N.I, which gave the Irish Government an official advisory role in the affairs of Northern Ireland. The agreement, considered one of the most important developments in relations between Great Britain and Ireland since the creation of the Irish Free State in 1922, provided for regular meetings between ministers of the Irish and British governments on matters relating to Northern Ireland. He outlined cooperation in four areas: political issues; security and related matters; Legal affairs, including the administration of justice; and the promotion of cross-border cooperation. In the improvement of the political climate between Britain and Ireland, the heads of state and government of the two countries met to negotiate. Ireland and Great Britain agreed that any change in the status of Northern Ireland would only be possible with the agreement of the majority of the population of Northern Ireland and an Intergovernmental Conference was established to examine the political, security and legal relations between the two parts of the island. The agreement dealt a blow to northern Irish unionists, as it played an advisory role for the Irish government in Northern Ireland affairs through the Anglo-Irish Secretariat. The Ulster Unionist Party (UUP) and other trade unionists terminated the agreement and UUP MPs resigned their seats because of this issue (although 14 were returned in by-elections in 1986). The party organized mass protests and boycotts of city councils and filed a complaint against the legality of the agreement. These efforts, joined by the Democratic Unionist Party, failed to force the abrogation of the agreement. The agreement created the Anglo-Irish Intergovernmental Conference, composed of officials from the British and Irish governments. This body addressed political, legal and security issues in Northern Ireland, as well as the « promotion of cross-border cooperation ». It had only an advisory function – it did not have the power to make decisions or amend laws.
 The Conference would have the power to present only proposals « to the extent that these matters do not fall within the competence of a de decentralised administration in Northern Ireland ». . . .