Learn that bloodshed couldn’t win in the end

and 1973. The Saville Inquiry into Bloody Sunday in 1972 said he “probably” carried a sub-machinegun during the killings of 14 unarmed protesters by soldiers.

Yet, curiously, McGuinness objected strongly when quoted in a book as describing British soldiers as “fuckers”, rebuking the author Kevin Toolis: “I never used that word!”

Neither did he drink or smoke, partly in case any addiction might weaken him under interrogation. He prayed, attended church and was regarded as incorruptible.

Along with physical courage and ruthlessness, these were all traits that built trust with the rank and file IRA members. Aged just 22, he was picked to join a seven-man IRA delegation flown to secret talks with Home Secretary William Whitelaw in 1972.

The peace talks failed but they helped forge the partnership of McGuinness and another delegate, 23-year-old Gerry Adams from Belfast.

McGuinness once said he left the IRA in 1974. But he is believed to have risen to Chief of Staff, stepping down in 1982 to pursue the new strategy of obtaining a united Ireland through “the Armalite and the ballot box”.

He would justify what he called “armed struggle” by comparing the position of Catholics in Northern Ireland with blacks in South Africa. But in his later years he said bombs alone were not a solution. “There are no military solutions — dialogue and diplomacy are the only guarantee of lasting peace,” he maintained.

Many were baffled by the relationship between the former terrorist commander and DUP leader Ian Paisley, yet both were political strongmen with strong religious convictions. When Paisley died in 2014, McGuinness declared: “I have lost a friend.”

Today’s relative peace in Northern Ireland was possible because the IRA gunmen and bombers knew the grandfatherly figure who shook hands with the Queen was, despite appearances, one of their own. @JoeMurphyLondon

‘There are no military solutions — dialogue and diplomacy are the only guarantee of lasting peace’

Martin McGuinness