By the kind of uncanny coincidence that would tickle his psychogeographically minded friends Iain Sinclair and Peter Ackroyd, Michael Moorcock’s publishers have recently moved offices to the same corner of London occupied by his latest novel, The Whispering Swarm; and just as their rather swanky embankment premises are called Carmelite House, so does the religious order provide Moorcock with one of his key characters.

It is a Carmelite monk who leads the book’s teenage protagonist, one ‘Michael Moorcock’, from an ABC teashop to a mysterious enclave just off post-Blitz Fleet Street. There, behind a ‘battered oaken gate’, the precocious journalist and budding science-fiction writer is introduced to ‘Alsacia’, a secret part of London that functions as ‘some form of giant time machine’, enabling our hero to meet characters such as Dick Turpin, the three musketeers and all manner of cavaliers and roundheads.

Clued-up fans of the 75-year-old writer — doyen of the science fiction and fantasy community thanks to dozens of hugely innovative novels and his editorship of the iconoclastic New Worlds magazine in the 1960s, and also author of more ‘literary’ novels such as the acclaimed Mother London — will have already spotted fact intruding into the realm of fiction. The Whispering Swarm is a hybrid, part autobiography, part novel. Why fictionalise your life, I ask him, when we meet in a backstreet pub near ‘Alsacia’? Why not write a straight autobiography? At first, he replied, it was a simple matter of not wanting to hurt people’s feelings: ‘If you tell the truth, even if you’ve no thought of doing it, somebody’s nose is put out of joint, they’re upset in some way. I just didn’t want to do it.’

But then he realised that there was potential for something more fruitful. ‘I started to think about the nature of autobiography and also about the nature of fantasy, and the purposes for which you use fantasy in all different ways, including the kind of self-justifying things that I know I did.’ In the book — and, indeed, in his life — the burgeoning writer marries and has children young, but his marriage founders in the face of his indefatigable creative energy, here figured as his periodic adventures in the secret parallel world. ‘A lot of the book was actually emotionally very hard to write,’ Moorcock tells me, ‘because I was facing truths I didn’t particularly want to look at. You always come to the idea that you’ve reached a certain level of self-knowledge and so on, but I don’t think you’re ever really right.’

It took five years to complete, not every writer’s idea of dragging their heels — but then not every writer has at times knocked out 15,000 words a day; he still remembers his horror when 1978’s Gloriana took him ‘six bloody weeks!’ But he also acknowledges that many of his serial works, including those featuring hipster secret agent Jerry Cornelius or Colonel Pyat, both members of the Moorcock ‘multiverse’, should properly be viewed as part of a lifelong project. Key to this alternate reality is the concept of the ‘Eternal Champion’, who must balance anarchy and order across dimensions and times.

So strongly is Moorcock identified with the world of science fiction and fantasy that it comes as something of a surprise when he tells me that, ‘If I hadn’t been asked to write a science-fiction novella in a pub not very far from here, in 1960 I think it was, I probably wouldn’t have been a fantasy writer at all.’ Possibly, he says, he would have got the same intellectual satisfaction from writing historical fiction. As a child, he read a handful of books belonging to his father and ‘probably left in his haste to leave the family home’ when Moorcock’s mother threw him out shortly after the end of the war; he had not fought, working instead in an office filled with women, who proved too much of a temptation.

Although his son kept up with him after his departure, his absence was something of a relief, because ‘He was the most boring man I’ve ever met, I think. Well, no, he was one of the three most boring men. So I was really glad that I didn’t have to live with him.’ What made him boring? ‘He was only interested in two things: cars and motorbikes. He swapped my train set when I was three or four, shortly before he left, for a motorbike. And that’s all he talked about, oh except The Wonderful World of Arthur C. Clarke, which he watched until he discovered that Arthur was gay and then he couldn’t watch it any more after that.’

But he was a fan of Edgar Rice Burroughs, which got Moorcock started; at 17, he became the editor of Tarzan Adventures, and began to write science fiction. Then, in 1964, he took over the editorship of the flagging science-fiction magazine New Worlds, determined, with his friends J.G. Ballard and Barry Bayley, to take the genre in an entirely new direction, one galvanised with moral and political purpose and infused with the tang of modernity, with writers such as Philip K. Dick and Ray Bradbury at its forefront. But the aim, Moorcock tells me, ‘was not to change science fiction’. Rather, ‘We felt that literary fiction had become moribund at that point, that it was essentially generic,’ studded with endless Lucky Jim-style characters. ‘There was really only one way to write a novel, it seemed; it was usually about a young man going through something or other, or sometimes a young woman going through something or other. And we felt that really fiction could be a bit livelier and perhaps address larger issues.’

Much of this had to do with the group’s belief in the power of the popular arts (‘We felt they could rise to become completely regenerative’), which has persisted throughout Moorcock’s career. A musician who worked with Hawkwind and Blue Oyster Cult, he likens the outsider appeal of science fiction back in the day — ‘There was nobody telling you how it should be’ — with that of rock’n’roll, when you used to turn up to studios with no idea ‘of what you were going to get when you came out’.

It’s clearly key to his approach to life. He describes himself as a Kropotkinist anarchist by disposition, and is appalled by the cult of individualism and consumer capitalism that has swept through modern life. In The Whispering Swarm,this relates particularly to the city of London, to which he still feels a deep tie despite he and his Texan wife Linda (his first reader, ‘she is the harshest editor. Red ink is her middle name’) dividing their time between homes in Paris and Austin. What does he feel when he looks at the capital now? He says he is depressed by its ‘Hollywoodisation’, the theming of pubs and so forth (‘It isn’t a myth, it’s a simple lie… and it’s there for one purpose, which is to make people nostalgic and spend a lot of money’). The problem, he says is that all this ‘aggressive consumerism makes people simplify their history in strange ways because they have to sell it somehow, and the more you simplify your myths and stories the fewer resources you have as a society’.

Much of this he places at the door of Margaret Thatcher, whom he believes sold off our ‘psychic silver’. But he hasn’t voted since New Labour, because he also hated Tony Blair. ‘So I stopped voting. I feel I shouldn’t have done, but I did.’ Would he vote for a Corbyn-led Labour party? He laughs. ‘That’s a leading question! Probably not. Well, I would vote for him, the way you’d salute a captain on a sinking ship.’

His next book, he says, will be the sequel to The Whispering Swarm, ‘the true story of my life’. He is so genre-bending that it is difficult to know what that might mean. Before he and Linda go off to catch the Eurostar back to Paris, I ask him if he wishes that all these distinctions would disappear altogether. ‘Absolutely. I think that authors ought to be stocked by name and not genre.’ So he’d like to appear simply under ‘M’? ‘Yeah, I would.’

One of his guiding lights, he tells me, is The Pilgrim’s Progress. ‘It was the first book I ever bought with my own money. It was threepence, secondhand… from that moment on, I believed you had to tell at least two stories in a story, if not more.’