Smash hit

For research, as well as garnering material from the British and London libraries, he went for a daily, far-flung afternoon walk: "Leytonstone, Forest Gate, anywhere to explore the terrain - walking was as much part of the research as reading books, to get a sense of atmosphere, a sense of place, and people, remnants of past times."

Given that the book is being hailed as the apex of Ackroyd's career - the definitive history of the city which obsessed him - it was, he accepts, "poetic" that he had a heart attack last November just after he had completed the final sentence. "London nearly killed me. I was sort of wrestling with the spirit of the place and it nearly finished me off. I was aware of a shortness of breath and thought it might be a virus. I went to hospital a few days later. I collapsed there. It seemed I had had three heart attacks without noticing."

He was in intensive care for a week, though on waking up and "feeling fine" he wrote an essay on William Blake for the Tate Gallery and a long book review for The Times. He says the heart attack has had no effect on his life: a famed sybarite, he still defiantly drinks a lot.

"It certainly wasn't a life-changing experience, though it should have been because I was so close to death," he says blithely, as the bustle of Smithfield - dot.commers, tourists and white-overalled market workers - flows beneath our restaurant. "But I didn't feel any intimate contact with anything Divine. When I came round I had a bottle of wine. What else was there to do but celebrate coming back to life? I had rather a good time in hospital, a good rest, and I shed some pounds. It's rather a vulgar concept that one's life should be changed by that kind of event. It didn't affect how I write. If you have a vision of world, it's not likely to be changed by temporary illness or a minor accident."

Along with this disavowal of the significance of the heart attack comes Ackroyd's scathing condemnation of current confessional literature. "I would never write a book about my illness," he says. "I don't like the confessional trend. It's vulgar. My private life does not inform my work. It was only in the 19th century that writers were persuaded that their private selves had any significance."

He hates talking about himself (unless he is drunk, which he isn't today). But this much he does impart. He is single, having broken up with his partner, Carl, earlier this year. He seems sad about this, although bluffly dismisses the break-up. He is moving from the rambling house they shared in Islington, North London, to a flat in Kensington.

The house, he says tightly, is now too big for him - though he denies being lonely. "The relationship came to a natural end. It's time for me to move on." He is also selling, he says, "to make a glorious profit - I always said there was nothing wrong with being a good businessman as well as a good writer. Shakespeare and Dickens were both consummate businessmen." (Four years ago, he signed a Pounds 1.5 million contract for eight books.)

He feels he may be single "for some time". His 24-year relationship with his literary assistant and partner Brian Kuhn ended when Kuhn died of Aids in 1994; Ackroyd nursed him through his final days ("nothing special, it had to be done"). Ackroyd's mother is still alive; they are both Catholics, and they never discuss his homosexuality - "it is not an issue. Why should anything be said?"

Work is foremost in his mind. He wrote The Mystery of Charles Dickens, the monologue currently starring Simon Callow at the Comedy Theatre, and will follow this first play with another about Shakespeare ("an extraordinarily opaque figure"), then a biography of the playwright, then an historical novel, then a biography of the Virgin Mary. "It's going to be tough writing about somebody who's immortal," he concedes. He says he likes the idea of retiring but can "happily imagine translating Dante when I'm 90".

But his obsession remains history - "always was, since school. I loved those Greeks and Romans but they were naughty". He never reads the papers, gets the news from Radio 4, got rid of his television earlier this year, hates mobile phones and the Internet. Bedtime reading is Samuel Johnson. He claims contradictorily to "contemplate things", and to "have no talent for introspection".

Whatever, he has transformed his childhood Catholicism into a "kind of spiritualism". He has never cared about dying ("death may just be the beginning"). He says he observes the "psychic geography" of the city as keenly as the physical: why different areas retain certain feels; why particular streets have incidents such as murders which recur through history.

For him, London is an "organically evolving city" gendered male, "thrusting not gentle. Most capital cities have a river of feminine deity. In London, we have Old Father Thames. The monuments of Big Ben, Monument and Canary Wharf are phallic. In times of distress and calm, London changes sex - the Great Fire of 1666 was, in his gender lexicon, female. "Women on the whole are bewildered by London, and find it very threatening. There is a general fear of getting lost."

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