[1] During her first term as prime minister, Thatcher had unsuccessful talks with both Jack Lynch and Charles Haughey on solving the conflict in Northern Ireland.

[3] Haughey resumed power shortly afterwards and took Argentina's side during the Falklands War, leading to the meeting scheduled for July 1982 to be cancelled.

British military intelligence informed Thatcher that she could not take the IRA head on and the likelihood of never-ending violence persuaded her to seek a political solution to the Troubles.

[6] The New Ireland Forum had been founded (with the backing of then-Taoiseach Garret FitzGerald) in May 1983 by John Hume in an attempt to undercut support for the IRA by bringing together constitutional nationalist parties from both sides of the border.

[6] Led by the Speaker of the House of Representatives, Tip O'Neill, and Senators Edward Kennedy and Daniel Moynihan, the Irish lobby regularly denounced what they considered British colonialism and human rights violations in Northern Ireland.

[6] 45 Senators and Congressmen (including O'Neill, Kennedy and Moynihan) wrote to Reagan criticising Thatcher's rejection of the Forum's report.

Reagan duly discussed Northern Ireland with Thatcher at their meeting, telling her that "making progress is important" and that "there is great Congressional interest in the matter", adding that O'Neill wanted her to be "reasonable and forthcoming".

[11][12][13] Sean Donlon, the Secretary General of the Department of Foreign Affairs, later claimed that "the intervention by Reagan was vital, and it was made possible by Tip".

[14] Michael Lillis, the Deputy Secretary General of the Department of Foreign Affairs from 1983 to 1985, similarly claimed that "O'Neill was very active and effective in mobilizing the President.

[19] In the communiqué accompanying the agreement, the UK agreed that all British Army patrols in Northern Ireland would have a civilian Royal Ulster Constabulary escort, save in the most exceptional circumstances.

In Portadown mobs attacked Catholic homes and a section of the motorway near Belfast way closed after nails and oil were strewn across the road.

Despite intensely violent loyalist protests in the year following the signing of the Anglo-Irish Agreement the RUC held the line, at the cost of a sharp deterioration in relations with the unionist community.

"[36] The UUP leader James Molyneaux spoke of "the stench of hypocrisy, deceit and treachery" and later said of "universal cold fury" at the Agreement such as he had not experienced in forty years of public life.

[41] Thatcher's close friend and former Parliamentary Private Secretary Ian Gow resigned from his Treasury post in protest at the Agreement.

[42] Concerns of a Rhodesia-style unilateral declaration of independence (UDI) were raised repeatedly during several confidential Anglo-Irish meetings in 1986, according to Irish State papers declassified in 2016.

Some senior Unionist politicians were sympathetic to the idea and had grown closer to loyalist paramilitaries, including DUP deputy leader Peter Robinson and UUP MP Harold McCusker.

[44] British civil service head Sir Robert Armstrong said that Unionist politicians had not considered the financial implications of an independent Northern Ireland, or how the move would be perceived internationally, especially in the context of the European Economic Community (EEC).

[46] In August 1986 DUP Deputy Leader Peter Robinson led a loyalist 'invasion' of the village of Clontibret in the Republic of Ireland, near the border.

However, Thatcher perceived the results of this to be disappointing because "our concessions alienated the Unionists without gaining the level of security co-operation we had a right to expect.

Sinn Féin's president, Gerry Adams, denounced the Agreement: "... the formal recognition of the partition of Ireland... [is] a disaster for the nationalist cause... [it] far outweighs the powerless consultative role given to Dublin".

[53] On the other hand, the IRA and Sinn Féin said that the concessions made by Great Britain were the result of its armed campaign, from which the SDLP gained political credit.

[54] Brian Feeney of the SDLP has suggested the agreement hastened Sinn Féin's 1986 decision to abandon abstentionism from the Republic's Oireachtas.

[55] Speaking in the House of Commons Jeremy Corbyn, MP for Islington North and later Labour leader, spoke to oppose the treaty saying that it ran counter to the goal of a United Ireland: Does the hon.

The former cabinet minister Tony Benn and Ken Livingstone, then leader of the Greater London Council, also opposed the agreement because they believed Britain should withdraw from Northern Ireland.

The by-elections called after the Unionist MPs resigned did not quite offer the electorate a clear-cut choice on the agreement due to the reluctance of the other parties to contest them.

The Alliance formally committed to fighting all the seats on a platform of support for the Agreement, but some local branches declined to select candidates.

In four constituencies where no party would oppose the Unionist MP a man called Wesley Robert Williamson changed his name by deed poll to "Peter Barry" (the name of the Irish Foreign Minister) and stood on the label "For the Anglo-Irish Agreement" but did not campaign.

The unionist parties between them garnered over 400,000 votes and over 71% of the total poll, but as no by-elections took place in the staunch nationalist seats of West Belfast and Foyle this latter figure is skewed.

[57] At a strategic level, the agreement demonstrated that the British government recognised as legitimate the wishes of the Republic to have an interest in the affairs of Northern Ireland.

Within ten years, however, the PIRA announced a (first) ceasefire, and both governments engaged in negotiation with the two sides to the Northern Ireland conflict, which led to the Good Friday Agreement.