A guide to the key moments in the Stevens inquiries in Northern Ireland.
Early 1987: The British Army's secret agent handling team, the Force Research Unit, identifies former paramilitary Brian Nelson as a potential recruit. It persuades him to return to Northern Ireland and rejoin the Ulster Defence Association. The FRU initially pays him £200 a week to supply it with information.
Autumn 1987: Brian Nelson, now codenamed 6137, begins supplying army intelligence with the UDA's list of possible targets. Nelson rises to become the UDA's intelligence chief.
November 1988: Criminal charges are dropped against Patrick McGeown, accused of helping to organise the March 1988 killing of two army corporals. Pat Fincuane was Mr McGeown's lawyer.
17 January 1989: Home Office minister Douglas Hogg tells MPs that some solicitors in Northern Ireland are "unduly sympathetic" to the IRA. His comments come after a briefing from senior RUC officers.
12 February 1989: Pat Finucane is shot dead in front of his family by members of the Ulster Defence Association.
25 August 1989: Controversy surrounds the killing of Loughlin Maginn, a 28-year-old Catholic whose family denies he is an IRA member. In an attempt to prove they only target republicans known to the security forces, loyalists pin up intelligence documents across Belfast - documents that have come from within the security services.
16 September 1989: John (later Sir) Stevens arrives in Northern Ireland to begin investigating allegations of collaboration between the security forces and loyalist paramilitaries. This appointment is the first of the three inquiries he is to run.
10 January 1990: The Stevens team has identified Brian Nelson as a key suspect and plans to arrest him and others in a dawn raid. Officers return to their secure investigation HQ hours before the planned arrests to find a fire raging in their offices. Fire alarms, telephones and heat-sensitive intruder alarms are not working at the headquarters. The fire destroys many of their files, though others had been copied and moved to England.
Brian Nelson flees Northern Ireland. He is eventually apprehended after he decides to try and return to Belfast.
January 1992: Brian Nelson goes on trial at Belfast Crown Court. At the trial, Colonel Gordon Kerr of the Force Research Unit, says Nelson's information allowed him to hand the police 730 reports of possible assassination attempts against 217 individuals.
"Brian Nelson was loyal to the Army." Brigadier Kerr told the court. "He wished to help the Army in its attempts to counter terrorism and to save life. He wanted to save life." Nelson is jailed for 10 years on five counts of conspiracy to murder.
April 1993: John Stevens begins the second inquiry into the security forces in Northern Ireland.
March 1998: United Nations special investigator Param Cumaraswamy accuses the Royal Ulster Constabulary of "systematic intimidation" of lawyers representing paramilitary suspects. He calls for an independent inquiry into the killing of Pat Finucane. The government rejects demands for an inquiry.
March 1999: A former paramilitary, Bobby Philpott, reveals to the BBC links between the security forces and loyalist groups. Mr Philpott tells the BBC series, Loyalists, that the Ulster Freedom Fighters relied on information passed from members of the security forces for its targeting of republicans.
April 1999: John Stevens, now deputy commissioner of the Metropolitan Police, returns again to Northern Ireland to launch a third inquiry specifically into the killing of Pat Finucane. He also begins to investigate allegations raised by campaign group British-Irish Rights Watch and the United Nations.
Summer 1999: Ken Barrett and another suspect are questioned in connection with the Finucane murder.
June 1999: Journalist Ed Maloney of the Sunday Tribune newspaper in Ireland publishes an interview with former UDA quartermaster William Stobie.
Mr Stobie says he was asked by a loyalist paramilitary leader to supply guns for the shooting of Mr Finucane. But he says he also warned the Royal Ulster Constabulary that the attack was being planned. The Stevens team subsequently charge Mr Stobie with conspiracy to murder. The Stevens Inquiry begins questioning members of the Force Research Unit.
26 November 2001: The trial of William Stobie collapses through lack of evidence after the chief witness, former journalist Neil Mulholland, says he is unwilling to appear because of health reasons.
12 December 2001: William Stobie is shot dead outside his home in Belfast. The Red Hand Defenders, a cover name used in the past by the Ulster Defence Association and Loyalist Volunteer Force, says it killed the former police informer.
May 2002: The government appoints retired Canadian judge Peter Cory to examine six controversial murders during the Troubles, including that of Pat Finucane. The government is committed to public inquiries if recommended by the judge.
18 June 2002: The BBC's Panorama programme broadcasts a special two-part investigation into allegations of collusion. The investigation details for the first time the workings of the Force Research Unit and alleges that elements of Northern Ireland's police and military intelligence collaborated with loyalist paramilitaries in relation to the death of Pat Finucane. It alleges a special branch police officer, who is not named, was involved in the killing of Mr Finucane by persuading loyalist to carry out the shooting.
25 June 2002: Sir John Stevens announces a postponement of the publication of his report into Pat Finucane's murder.
2 September 2002: Hugh Orde, the detective in charge of the day-to-day running of the Stevens inquiry, steps down as he becomes chief constable of the Police Service of Northern Ireland.
23 October 2002: Sir John Stevens announces a second postponement of the publication of his report into Pat Finucane's murder.
13 February 2003: Sir John Stevens confirms he is preparing papers for the Director of Public Prosecutions in relation to Gordon Kerr, now a Brigadier and the British military attache in Beijing.
11 April 2003: Brian Nelson dies of cancer in Canada. Following his release from prison he had been living under an assumed identity at a secret location in England.
17 April 2003: The "Stevens 3" report is published.