It was claimed that as head of the IRA's Northern Command he had advance knowledge of the IRA's 1987 Enniskillen "Remembrance Day" bombing, which left 11 civilians dead - something he denied.

What Bloody Sunday inquiry found about McGuinness

The inquiry into Bloody Sunday, when 14 unarmed civil rights protesters were killed by British paratroopers in 1972, concluded that although McGuinness was "engaged in paramilitary activity" at the time and had probably been armed with a Thompson submachine gun on the day itself, there was insufficient evidence to make any finding other than they were "sure that he did not engage in any activity that provided any of the soldiers with any justification for opening fire".

In 1993, a Central television documentary claimed that in 1986 he had been present at the interrogation of Frank Hegarty, an IRA informer who was later found shot in the back of the head. Mr McGuinness has denied all the allegations.

How he persuaded IRA gunmen to lay down arms

But his later role in using his credibility as a paramilitary commander to persuade IRA gunmen and their supporters to lay down their arms and support the peace process was recognised as central in bringing an end to the near-daily violence that had plagued the province since the late 1969 and claimed the lives of 3,532 people.