The Sunningdale Agreement was an attempt to create a Northern Ireland executive and a cross-border council of Ireland. Signed on December 12, 1973 at Sunningdale Park in Sunningdale, Berkshire.  The Unionist opposition, violence and a general loyalist strike led to the failure of the agreement in May 1974. In January 1974, the Ulster Unionist Party narrowly voted against further participation in the assembly and Faulkner resigned as leader to be replaced by the anti-Sunningdale Harry West. Parliamentary elections were held the following month. The Ulster Unionists formed the United Ulster Unionist Council (UUUC) as a coalition of anti-union unionists with the Progressive Union Vanguard Party and the Democratic Unionist Party to field a single anti-Sunningdale candidate in each constituency. The pro-Sunningdale parties, the SDLP, the Alliance, the Labour Party of Northern Ireland and the Pro Assembly Unionists, made up of Faulkner`s supporters, disagreed and clashed. When the results were de-reported, UUUC won 11 of the twelve constituencies, some of which were won by split votes. Only West Belfast has returned a pro-Sunningdale MP (Gerry Fitt). UUUC has declared that this is a democratic rejection of the Sunningdale Assembly and executive and has tried to bring it down by all means.
The 1998 Good Friday Agreement (GFA), on which the current system of decentralisation in Northern Ireland is based, is similar to that of Sunningdale.  Irish politician Séamus Mallon, who participated in the negotiations, called the agreement “Sunningdale for slow learners.” This claim has been criticized by political scientists such as Richard Wilford and Stefan Wolff. The former said that “it`s… [Sunningdale and Belfast] have considerable differences, both in terms of the content and circumstances of their negotiation, implementation and implementation.”  Council of Ireland provisions existed in the Government of Ireland Act 1920, but they had never been adopted. The Unionists were furious at any “interference” by the Republic of Ireland in its newly created region. In 1973, following an agreement on the formation of an executive, an agreement was reached on the reintroduction of an Irish Council to promote cooperation with the Republic of Ireland. Between 6 and 9 December, discussions took place in the town of Sunningdale in Berkshire between British Prime Minister Edward Heath, Irish Prime Minister Liam Cosgrave and the three pro-agreement parties. On 21 November, an agreement was reached on a voluntary coalition of pro-agreement parties (contrary to the provisions of the Belfast Agreement, which defines Hondt`s method for electing ministers over the main parties in the Assembly). The distinguished members of the executive were former Unionist Prime Minister Brian Faulkner as Chief Executive, Gerry Fitt, Head of the SDLP, Deputy Director General, future Nobel Laureate and Leader of the SDLP John Hume as Trade Minister and Chairman of the Oliver Napier Alliance Party as Minister of Law and Head of the Law Reform Office. The other members of the executive were the Unionist Basil McIvor as Minister of Education, Unionist Herbert Kirk as Minister of Finance, Austin Currie, SDLP member, Minister of Housing, Unionist Leslie Morrell as Minister of Agriculture, Paddy Devlin, SDLP member, Minister of Health and Social Affairs, Unionist Royist Bradford as Minister of the Environment and Unionist John Baxter as Minister of Information.
 This new executive, made up of the aforementioned members, took office and had its very first meeting on 1 January 1974.  The UUP was deeply divided: its standing committee voted by 132 votes to 105 in favour of participation in the executive.