Some believe McGuinness didn't leave the IRA until its campaign end in 2005
Martin McGuinness was an IRA man before he entered politics and some believe he didn't leave the leadership of the Provisional IRA until it ended its campaign in 2005. Security Correspondent Allison Morris reports
In 1972, at the age of just 21 Martin McGuinness represented the army council of the IRA at secret talks with then Northern Ireland Secretary William Whitelaw.
Also at the London talks were the then IRA chief of staff, Dáithí Ó Conaill, Seán Mac Stíofáin, Gerry Adams, Seamus Twomey and Ivor Bell.
Despite his youth McGuinness played a key role in the talks which ended in failure after Mac Stíofáin demanded British withdrawal from Ireland. It would the first of many engagements with various British governments, firstly as the spokesperson for militant republicanism and later Sinn Féin.
McGuinness originally joined the Official IRA before becoming a member the then fledgling Provisional movement.
He was second-in-command of the IRA in Derry in January 1972 when 14 civil rights protesters were killed in the city by soldiers in what became known as Bloody Sunday.
This event more than any other shaped the thinking of the Bogside republican. In his evidence to the Saville Inquiry in 2003 he said: "At the time of Bloody Sunday I was adjutant to the Derry IRA. Within two weeks, I became officer commanding of the Derry IRA".
Later that year he was pictured as part of a colour party at the funeral of IRA man Colm Keenan.
The following year he was convicted by the Special Criminal Court in Dublin, after being arrested close to a car containing 250 lbs of explosives and nearly 5,000 rounds of ammunition, he defiantly told the court "I am a member of Óglaigh na hÉireann and very, very proud of it".
Shortly after his release from prison he was once again convicted of IRA membership and served a further period of imprisonment in the Republic.
While he always maintained this was the end of his IRA career, journalist Peter Taylor claimed in his documentary Age of Terror, shown in April 2008, that McGuinness was the head of the IRA's Northern Command at the time of the 1987 Enniskillen bombing, which left 11 civilians dead.
He was also the subject of a two-part Panorama investigation by journalist Roger Cook, that included information supplied by an IRA source, who later turned out to be west Belfast man Freddie Scappaticci.
The documentary accused McGuinness of attending the interrogation of informer Frank Hegarty. His mother Rose appeared on the programme and said her son had been promised he'd be safe if he returned to Derry but was later shot dead.
This was denied by McGuinness both at the time and at various stages throughout his political career.
Scappaticci also told the Cook report that McGuinness was still head of the Northern Command of the IRA until the early 1990s when it was agreed he would take a more prominent role in Sinn Féin and help formulate the political strategy of the party.
In 2005, Michael McDowell, the minister for justice in the Irish government at the time, said following the Northern Bank robbery that McGuinness, Gerry Adams and Martin Ferris, were members of the seven-man IRA Army Council. It was denied by all three.
In 2009 in an interview with the Irish News veteran republican Ruairí Ó Brádaigh recalled that in 1984, a year after he resigned his position as president he was involved in a serious car accident.
Both he and his wife spent several weeks in hospital at the time when an internal battle within Sinn Féin was raging which would eventually lead to the walk out of 1986.
Ó Brádaigh despite their political differences spoke with affection of Martin McGuinness making the journey from Derry to the hospital in Dublin where he was being treated, while the rest of the young Belfast leadership stayed away. Ó Brádaigh said he had continued to respect McGuinness as both an "IRA volunteer" and as a person.
One ex prisoner told the Irish News yesterday that it was only the "influence of the leadership" and McGuinness specifically that persuaded the more militant IRA members to pursue a political path.
"He held the respect of all the men and women in the movement, we trusted his leadership.
"I will admit now that on the day of the referendum (GFA) I was still undecided whether to vote yes or no and it was only the words of the leadership, and specifically Martin McGuinness, that persuaded me to vote yes.
"He lead from the front, there are many who argued that he should have walked away and collapsed the assembly long before he did, it was only because of the measure of the man that he stretched it out as long as he did and tried all in his power to make it work".