It may be half-a-century ago, but Eamonn McCann still remembers every twist and turn and every RUC baton clout from that "unforgettable" civil rights march in Duke Street in Londonderry which changed Northern Ireland forever.
And as the 73-year-old writer, journalist, politician and protestor talks of RUC ambushes and beatings, it's obvious that the fire still burns as fiercely as it ever did in the belly of one of the men at the forefront of the nascent civil rights movement in his home city.
Many of the people from that ground-breaking - and head-splitting - march on October 5, 1968, when police ruthlessly wielded their batons against demonstrators, have passed away, though they still live on in the RTE news pictures, which were captured by cameraman Gay O'Brien and which were flashed all around the world.
McCann's voice has never been silenced, however. And, despite battling against a cold, he's every bit as rambunctiously articulate and passionate as he was when he marched the streets of Derry and addressed protestors via a bullhorn, though his was the very antithesis of megaphone diplomacy.
McCann still marvels at how the day unfolded. He was part of the team of people who organised the march and he says they weren't called the "ad hoc committee" for nothing.
"It was a very loose grouping," he adds. "Most of us were from a labour or socialist background, but there were others, as well. I don't think we had a chairman, or a secretary, or anything like that. It had no structure.
"It had just developed from the Derry Housing Action committee, which was itself a loose coalition of radicals of some sort or another."
On the morning of the march, McCann was arrested along with colleagues Ivan Cooper and Charlie Morrison as they drove around the city in a loudspeaker van, calling on people to attend the march.
McCann says: "I was shouting through the megaphone, urging people to come out. We were taken to Victoria Barracks on the Strand Road and we were held for a couple of hours before the RUC let us go without any explanation of why we'd been arrested.
"We hadn't been questioned about anything. Throughout it, all we could hear were dogs barking, but they never appeared on the streets.
"I suspected the cops didn't know what they were doing when they picked us up. But they knew exactly what they were doing later on in Duke Street."
McCann says that the banned march had been due to take a different route, up Simpson's Brae on to Spencer Road, but couldn't go in that direction because of the huge number of RUC Land Rovers blocking their path.
As the marchers moved down Duke Street, however, he says the police, who had come from behind them, from Simpson's Brae, started to attack the protestors, too.
"I realised this wasn't a police operation to disperse an illegal crowd, it was a punishment for being there," adds McCann, who recalls that, in the middle of the mayhem, a meeting was held which he, Austin Currie and Ivan Cooper addressed while standing on a chair.
"It was all very chaotic, but it was also very uplifting in its own way."
However, the reality of October 5, 1968, according to McCann, is that, if the police hadn't gone on the offensive and had instead allowed the march to go ahead, no one would have paid much attention to it.
He says: "It's a paradoxical thing, but political violence helps those against whom the violence is aimed, rather than those who are perpetrating it. And that's the way it was in Duke Street. The 60 seconds of Gay O'Brien's pictures led the news bulletins as far away as Australia and America, as well as in Britain, which had very little interest in Northern Ireland, Orange or Green.
"There was no logistical reason for attacking the march. To me, it was a political matter, an attempt to put manners on the civil rights trouble-makers, as the authorities would have seen them."
McCann says he "took a couple of clouts" from RUC batons on his shoulder and his side, but dismisses the injuries as "nothing".
With the passage of time, the violence of Duke Street has been cited in many quarters as the start of the Troubles.
McCann insists: "I'm not saying that it sparked anything afterwards.
"October '68 wasn't, in itself, responsible for it. The roots of what happened over the last 50 years are very deep in history, but Duke Street certainly was the beginning of a dramatically new phase in Northern Ireland. We realised soon afterwards that things were never going to be the same again; that this was going to be a plot point in the narrative of Northern Ireland.
"Obviously, I didn't know what was coming, or that the future would hold so much violence. No one could have foreseen the 30 years ahead."
In recent times, there's been controversy over claims by Sinn Fein that they and the IRA were the key drivers behind the formation of the civil rights movement.
McCann says: "Sinn Fein rewrite history because they can't face the truth of history.
"It seems to me that there's been a systematic attempt by them to hijack what others have done and not just in terms of civil rights in Northern Ireland.
"If you listen to Michelle O'Neill and Mary Lou McDonald, you would think they were an integral part of the repeal of the Eighth Amendment in the south. They were no such thing. They jumped on the bandwagon a few months before the referendum."
McCann says republicans have also rewritten the history of their armed struggle.
He adds: "They would have you believe that it all happened in the interests of equality. It did not. The IRA were fighting to get the British out of Ireland. It was all about 'Brits out'.
"Republicans have to be contested over October '68, because if you don't, it's going to be difficult to contest the Provo narrative over the rest of the Troubles. It's important as citizens, journalists, writers and academics to get this right and to say that, implicitly at least, Sinn Fein is lying about October 5.
"They should be ashamed of themselves, but I don't suppose for a moment that they are."
McCann admits that, in the early days of the Troubles, he was tempted to take up arms, but only in self-defence.
He says: "At one point, I was part of a group that went into Donegal to sort of try to learn to use arms, but that was at the time just after the shootings and burning of Hooker Street and Bombay Street in Belfast.
"It seemed to me - and it still does - that people have a right to defend themselves. But that initiative, such as it was, to create defence committees that wouldn't be answerable to any political organisations didn't work, because it was overcome by the Provos and other armed groups, including the Official IRA."
McCann says the paramilitary organisations who emerged on both sides and claimed they came into existence to defend beleaguered people weren't telling the truth.
"They were fighting for ideologies and, in some cases, like the Shankill Butchers and so on, they were acting out of sheer hatred," he says, adding that he won't dodge the question if he was ever tempted towards violence at any other time.
"Of course I was, especially after Bloody Sunday and the Widgery Report. But, politically, it was always wrong - and it is still wrong.
"Once a secret army present themselves as the representatives of the people, they are telling lies. If you are a secret army you cannot be - and they weren't - accountable to the people in whose name they were carrying out their armed struggles.
"That on its own would deter me from being associated with them and certainly becoming a member."
McCann, instead, took a different path which led him via a circuitous route to Stormont as an MLA for People Before Profit.
And now a new BBC Northern Ireland documentary shows how McCann went, not to hell and back, but rather to Stormont and back, getting himself elected to the now-stalled Assembly after five decades of trying, before he lost his seat 10 months later in a snap election.
In Eamonn McCann: The Long March, the activist says it was the people and not the paramilitaries, or the politicians, who got things done, adding: "The only thing that ever got us anywhere in this town (Derry) was not parliamentary manoeuvre. In my view, it certainly wasn't armed struggle. What it was was the sound of marching feet."
The documentary also features a discussion between McCann and his friend Bernadette McAliskey as they reflect on what the civil rights movement achieved.
Speaking to the Belfast Telegraph, he says: "Things have, of course, changed. And the progressive reforms mainly came in 1968, '69 and '70 through the civil rights movement - an end to discrimination, gerrymandering and the tackling of housing issues.
"The changes were achieved by the people-power strategy of the civil rights movement. There's still a long way to go, however.
"We are still as divided as ever, but the political patterns nowadays at the top in Northern Ireland do not reflect what is happening deep down at the grassroots.
"The DUP do not speak for the majority of the Protestant people when it comes to issues like women's and gay rights and austerity.
"The number of Protestant people who vote for the DUP t hrough gritted teeth should worry that party enormously, but of course they may be too arrogant to worry about anything."
McCann regrets that he didn't get longer in the job in Stormont, which he says was already crumbling before he arrived.
He says he's doesn't foresee an early return, but he adds that Northern Ireland is "trembling with change" and not just because of what may come in the wake of Brexit.
He says the growth of the women's movement and grassroots organisations across Ireland has given him great heart and reinforced his belief that change can come from the bottom up and not from the top down.
Eamonn McCann: A Long March, BBC One Northern Ireland, Monday, October 8, 9pm