In the spring of 1968 Tariq Ali - a young romantic-looking Marxist with a droopy moustache in self-imposed exile from Pakistan's military dictatorship - galvanised British public opinion against the Vietnam war, becoming the figurehead in a campaign that culminated in 25,000 people marching on the American Embassy in London. It marked the start of a year that earned its place in history through a succession of shattering upheavals on every continent, a year recently documented by Tariq Ali in his book Marching In The Streets.
It had been another march 12 years earlier that "first politicised" him, Tariq Ali remembers and one which curiously has an Irish dimension. He was 12 and at a school run by the Christian Brothers in Lahore where his left-leaning parents had sent him in preference to the British-run school for the children of Pakistan's elite.
"It was in 1956 and university students were on strike, demonstrating against the British invasion of Suez. They came to our school because they thought the Irish Brothers were all Englishmen and they were chanting slogans against the Reverend Brother Xavier Henderson. Suddenly, to my amazement, he leapt on top of a car and started addressing them. He'd always had fingers which were slightly bent and the joke among us boys was that he masturbated too much. And he lifted up his hand and said, `see these fingers? These fingers are like this because I was a member of the IRA, fighting against British imperialism just like you are doing. And they were broken by the Black and Tans.' Suddenly all these university students started chanting `Long live Brother Henderson'. And he closed the school down and we all went on the march. That was my first political act."
Political acts in the revolutionary sense came to an end for Ali in 1980 when he left the International Marxist Group after the disintegration of the far left in Britain (brilliantly parodied in his first novel Redemption). "I just couldn't take the internecine warfare, the sectarianism, the factionalism, the refusal to see reality for what it was." He decided to move sideways and began to write.
These days Tariq Ali is a busy man. In addition to Marching In The Streets, last month saw the publication of Fear Of Mirrors - a fascinating and highly accessible fictional unfolding of the rise and fall of communism seen from the other side of the Iron Curtain. He has just delivered another novel to his publisher and is working on the next. And on Thursday, the first episode of Big Women, a four-part drama written by Fay Weldon, produced by Ali and made by his production company, was screened on Channel 4. It traces the rise - and fall - of feminism. The idea was Ali's own, inspired by the bust-up of the feminist publishing house, Virago. "Hearing the stories of what happened from every side was very dramatic," he recalls. Just listening to some of the women involved I just felt that this was television drama and went straight to Fay." Weldon's novel of the same name which appeared nine months ago was actually written after the television scripts.
Big Women is Tariq Ali's first mainstream television drama and the production office where we meet in down-at-heel north London is full of the usual glossy publicity material. Although the trademark moustache is now grey and clipped, Ali still cuts a charismatic figure, well-built, tall, his revolutionary zeal gloved in patrician authority, legacy of his aristocratic birth.
Tariq Ali has been involved with Channel 4 since its earliest days when Jeremy Isaacs came looking for "dissenting voices". The result was The Bandung Files, a series of critical documentaries on Third World history, art and literature, followed by Rear Window, a series which explored the divide between culture and politics. The breadth of subject matter is impressive, from portraits of film-makers, artists and writers, to the cultural implications of the Holocaust.
From a re-evaluation of Ghengis Khan to Trotsky's home movies and 24 hours in the life of Dakar seen through the eyes of Senegal's Youssou N'Dour. Both series were eventually dropped because, believes Ali, they made the powers that be uncomfortable.
"They showed that television could be quite a daring thing and in their own sort of shame and guilt in the crap they were doing, they became very hostile."
It would be impossible, he believes, to make such series now. "The people who nourished, nurtured and encouraged dissenting voices are no longer there. Largely, television is staffed with time servers and people climbing the greasy pole who can shift with ease from one network to another."
The infrastructure he put in place for the Bandung Files was not wasted, however. Having discovered that "reaching the brain through television" was what he enjoyed doing most, he simply moved sideways again. Already familiar with the power of drama to bring history to life through two stage plays written in collaboration with playwright Howard Brenton, he began a series of collaborations with non-mainstream film-makers. First came Partition, with Ken McMullen, set in a lunatic asylum on the eve of the division of India and Pakistan. Then came a series on philosophers: most memorably, perhaps, Wittgenstein with Derek Jarman.
Through drama Tariq Ali continues to chip away at the establishment, but these days it's a piecemeal business. "The way capitalist politics is functioning is increasingly authoritarian, designed not to wipe out perhaps but completely to marginalise dissenting voices."
He sees it as the legacy of the "steamrollers" of Reagan and Thatcher. "There is dangerous monolithic political culture in these countries, which you feel very strongly in Britain with New Labour. There is a fundamentalist streak which is not healthy."
Fundamentalism is the greatest danger facing the post-communist world, he believes. An Egyptian friend, a fellow former Trotskyist, recently told him that the Maoist leaders from the 60s and 70s were now all Muslim fundamentalists. On a personal level he has always been "a kaffir" - an un-believer. "I never believed in God. Never." Neither did his communist father though Ali senior insisted his son learned the mythology of his culture and a tutor was duly hired who proved equally radical. "Half way through I began to question him. I said, `but is it true?' And he said, `but that's not the point'." It served Tariq Ali well: the trilogy of novels he describes as "a fictional account of the clash between Islam and Christendom" would have been inconceivable without such a grounding.
The first, Shadows Of The Pomegranate Tree, is a fictional account of the aftermath of the fall of Islamic Spain seen through the eyes of an aristocratic Moorish family. Although highly praised by the British press when it was published in 1992 ("A book to be relished and devoured" - Independent; "An imaginative tour-de-force - Sunday Telegraph) it is outside Britain, where it is now out of print, that Tariq Ali has seen this praise translated into sales. It won the Best Foreign Language Fiction prize in Spain, made the bestseller lists in Germany and looks set to do the same in Brazil and last week came the news that Shadows Of The Pomegranate Tree was number one in the Bosnian bestseller list.
The second in the trilogy, about the crusades, has just been delivered to his publisher. And the third, centred on "the Ottoman experience", is well underway. All three, he says, are total fiction, in the spirit of Gore Vidal's Creation. "It's sort of re-creating lost worlds. But they've all got quite a modern ring to them. Which is why the Bosnians love Shadows Of The Pomegranate Tree so much. It reminds them of what's happening there."
So much so that he's been invited to go to Sarajevo. However, when the British Embassy was told of Ali's impending visit, the response took the publisher by surprise. "They don't like you, these bureaucrats," he wrote. "The reaction was of utmost resentment."
"It's funny, it's almost as if they don't want me to part of them, it's almost as if they resent one writing fiction. Because in this particular culture in which we live, there's such a divide between politics and aesthetics, that when you mix the two people get very nervous." And the scourge of the establishment roars with laughter.
Marching In The Streets, Bloomsbury, £20 in the UK. Fear Of Mirrors, Arcadia, £11.99 in the UK. Big Women, Thursdays on Channel 4