Every day, she wakes up and writes for four hours; every day, she eats exactly the same lunch. "I write every morning," she tells me, "From about a quarter to nine to a quarter to one. It might be nine to one, or 8.30 to 12.30." The lunch never varies. "Bread and cheese and salad and fruit. Not much cheese." She has been writing for 36 years, and has produced around 50 novels. As she gets older, she gets faster; now she writes at the rate of two books a year.
Rendell is 69, but looks taut and fit, and has dyed her dark hair a glamorous shade of blond. She works out, she tells me - she uses weights and a treadmill at her house in Maida Vale, London, and she walks, often several miles a day. She thinks up her stories as she walks; exercise, she believes, frees the mind. Apart from her small portions of cheese, almost always Gruyere, she shuns dairy products. She never eats red meat. She avoids creamy sauces, and anything "fatty". "Yes," she says, "I'm in good shape."
She keeps moving in other ways, too. Since she started writing, she has moved house 18 times - a house every two or three books. For some reason, she moves house compulsively. Mostly, she has two houses - one in London and one in Suffolk. "I enjoy moving. I like to be in a new place. Settling down doesn't appeal to me much. I like the whole business of it. And I love the first night in the new place."
Rendell has lived in Chelsea and on Hyde Park, in Highgate and Hampstead, in West Hampstead, Kilburn, Cricklewood and Regent's Park. She is, of course, thinking of moving again - perhaps to Kensington or Westminster. She says, "I like it. It's a sort of indulgence of mine. It's a kind of hobby, I suppose. I don't really have any hobbies. It's an odd one, I know."
She falls silent, pondering. This is something she does often. She says, "I can never buy any more furniture. It's awful. I used to have a house in Aldeburgh, and I sold that this year, and when I moved out of that, I found that I owned 67 chairs. I had three houses at the time. I mean it was all ridiculous. It's awful to live like that. Sixty-seven chairs? I must have had 59, and somebody had eight William Morris chairs which they offered to sell me, and I couldn't resist them, so that brought it up to 67. But that wasn't counting sofas - there are a lot more of those. So it's all crazy. But I think I've got that in order now."
We meet in Edinburgh, in the lobby of the small, unflashy hotel in which she is staying. She had come to Edinburgh to deliver a lecture on the history of women writing about sex - a history of repression. "I thought it would be fun," she says. "That's probably the only reason I would do it." In the lecture, she pointed out that, even though people didn't realise it at the time, the Bronte sisters boiled with passion. She herself, she says, has not felt repressed as a writer. "I don't write pornographically, not because I object to it, but because it's not very effective," she says. "It's better to do things by suggestion."
As Ruth Rendell, she has tended to write clever, twisty plots about English provincial police procedure. As Barbara Vine, her subject is the fact that ordinary, civilised people harbour depths of madness, and might easily fly off the handle and kill. Guns are used sparingly - people are bludgeoned to death, or kidnapped. The moment of death is described with the lightest of touches. Some critics believe that Vine is taking over - or, to put it another way, that Wexford, a man who, she has hinted, is a male version of herself, is having to deal with increasingly dark aspects of the human criminal mind. "One critic recently wrote, 'She should thank God for Barbara Vine,' as if, of course, Barbara Vine came from outside and took me over." Again, she ponders for a moment. "But I know what he means," she says.
Is Vine taking over? Is Vine the self she struggled to suppress, but could not? She sips her orange juice. She is wearing a woollen sweater, trousers, smart shoes with a little heel. "I couldn't have written the Vines under the name Rendell, and I can't account for that."
Rendell is waiting for a cab. We will continue the interview in the taxi, and then at the airport. Casually, I ask her about her childhood. For a second, she looks stunned.
This reminds me of the first time I met her, at her last house but one in Suffolk. I had come to talk about Barbara Vine, whose novels A Dark- Adapted Eye and A Fatal Inversion had impressed me with their strategies of subtle horror. I pressed the doorbell. Rendell, then dark-haired, opened the door and let me in; moments later, she looked at me with an expression of shock, as if she had just woken from a dream, or as if I were an intruder. Then we sat down, at a shiny, antique table, and talked about murder. Barbara Vine, I think, had answered the door; but the friendly, talkative woman who made me a cup of tea had been Ruth Rendell.
Now she looks straight at me, and says, "No, I don't want to do that, not doing that, never describe my childhood, no, I'm not going to talk about that."
The taxi arrives. Rendell, with her modern black shoulder bag and youngish clothes, might, from any distance, be a woman entering, rather than leaving, middle age. She walks like a young woman. The taxi pulls away into the sharp August sunshine. This is not Rendell's favourite weather. "I rather like a kind of still, grey day that sometimes we get in summer," she says. "I don't expect the sun to be always shining, or even want that to happen."
What do we know about Ruth Rendell? She was born in 1930. Her mother was born in Sweden and brought up in Denmark until the age of 12, when she came to England. Both parents were teachers. She grew up in Leyton, suburban east London, and went to school a few miles away in Loughton. She began her professional life as a journalist on a local paper, and married another journalist, Don Rendell. She divorced him in 1975, and married him again in 1977. (Don Rendell died earlier this year, of cancer.) Her only son is a social worker living in Colorado; in his professional capacity he dealt with the aftermath of the Columbine High School shootings.
You can hear the Leyton in Rendell's accent, although these days it is overlaid, not unpleasantly, with something else - the clipped tones of an academic. The most recent Vine, The Chimney Sweeper's Boy, is about Gerald Candless, a novelist with a clipped, academic demeanour who had spent his life blocking the horrors of his Leyton youth out of his mind. In the book, the narrator's clinical eye is cast along the streets of the suburb, which "sounded unattractive, even slummy".
Sitting in the taxi, I say, "You write about scary things..."
She says, quickly, "I don't only write about scary things."
"But do you ever scare yourself?"
"No. Never. I'm detached. I'm not affected by what I write. I can move myself by scenes which depress me. But they don't frighten me."
Then she says, "I was moved when the family was shot in A Judgement in Stone." In this shocking book (filmed in 1995 by Claude Chabrol as La Ceremonie) a young girl is employed as a cleaner in a middle-class household; in a frenzy of self-loathing and repressed class hatred, she kills them all with a shotgun. Rendell says, of the middle-class family, "I'd taken great pains with these people, and I was very fond of them. I still think that they were a very good family, and I was quite pleased with that, and I didn't want to kill them, but I had to, I'd already done it in the first line, and I was affected by that, it quite upset me, but that's an isolated incident. It doesn't happen very often."
We go round a roundabout. She says, "I can't sum up my books. They're all rather complicated. Sometimes I think they're too complicated. But that's the way I am.When I start to write a book, my head gets full of all kinds of detail."
What, I ask her, are the Vine books about? Rendell says she finds it hard to analyse them. "Really great fiction or drama," she tells me, "Can be summed up in one word, but mine isn't in that category. For instance, you can take the plays of Shakespeare, and you can sum them up in one word. Macbeth is about remorse. Othello is about jealousy. Antony and Cleopatra, which, incidentally, is my favourite play, is about passion. I can't sum up my books."
Still, she tries. A Fatal Inversion, a book which turns on an incidence of baby-snatching, is, she says, about "the inability of young people to be responsible, which is quite natural. It's about a lack of restraint and self-discipline." No Night is Too Long is "about selfishness, about vanity, about a very, very good-looking person who thinks his handsomeness gives him the right to do anything".
We arrive at the airport. Airports, she says, do not make her feel trapped. If anything, she says, she is "slightly agoraphobic. I'm not very fond of being in the middle of a big empty field." Then she says, "I'm not going to say I would become a gibbering maniac. But I don't like it. I would get out of it fast." At her most recent house in London, she sleeps in a four-poster bed, which she had specially made. She doesn't always close the curtains around her, she says. "But I like to feel enclosed."
At the check-in desk, there is a confusion involving Rendell's ticket. "This is ridiculous!" she says. But her good humour returns. For a long time, she tells me, she did not feel alienated by the modern world. But now she's beginning to. "I resist it, I struggle against it, but I can't help it now. I do feel there are too many unpleasant things.These days there are things that, try as I might, I can't like."
We walk along. Rendell walks fast. One of the things she can't bring herself to like, she says, is, "Dreadful words that have crept in. Horrible cliches. Things like the word 'at' being replaced, not in a computer context, by that symbol. Because I know that the people who use it think it's terribly clever."
She considers the issue further. "Instead of writing 'your', people write 'you're'. It's like the greengrocer's apostrophe."
We sit down. Rendell orders water. Somebody else orders "mochaccino". Rendell says, "That's something else I don't like, but really I've no business to say such a thing." Other things she doesn't like: the dumbing- down of television, the "spoiling of the Six O'clock News". She says, "I barely watch TV any more, but I do listen to the radio and I suppose they'll mess that up soon."
Still, she says, it is "bad for one's character to be always dwelling on things that one doesn't like."
In Harm Done, the latest Vine-shadowed Chief Inspector Wexford book, Wexford must wade through the minds of sexual abusers and perverts. Rendell's fictional country town, Kingsmarkham, is looking darker, more frightening. In the book, a young girl disappears, only to reappear a few days later with disturbed memories of her abductors. The same thing happens with another girl. Then a baby goes missing. There is a sub-plot involving a paedophile.
Rendell concedes that the influence of Barbara Vine is creeping into the Ruth Rendell books. She does not make the assumption that people are nastier than they were in the past. Perhaps, in the age of television, we are simply better informed about the human condition. "The crime we are best at, in Britain," she says, "is stealing. We don't have a gun culture, thank God. It's terrible, the effect the gun culture has on America. One feels like saying, like Madame Roland at the guillotine: 'Oh, Liberty, what crimes are committed in thy name.'"
She says she was "somewhat stunned" to be offered a peerage, but that she spends a lot of time at the House of Lords. The House, she says, is "different from most people's conception of it, which is that it is generally full of very, very old men who sleep all the time." In fact, she says, these men have "razor-sharp minds". She is in favour of reforming the House.
Rendell uses her position to work for charities, including the NSPCC. She is, she says, "not one of those peers who just pops in for an afternoon every three months". Her maiden speech, was on the subject of literacy and lasted seven minutes. What point was she making? "Well, basically, that it is a good thing." She is "very pleased with honours. I'm not blase about them. Goodness!" She did better than she thought she would. I thought I might get an OBE one day, but I didn't expect to get the CBE and the peerage."
Rendell slings her bag over her shoulder and walks towards the departure lounge. She is working on two more Barbara Vine books. The first one, The Grasshopper, is about a group of people shadowed by life-changing events in the Eighties; the second will feature the reform of the House of Lords as its background. She shakes my hand and smiles. The last I see of her is the brush of strong blonde hair bobbing quickly through the security gate.
She is, she has said, "neurotic" about punctuality. She will arrive at her house in Maida Vale in time for lunch, where, because she lives a controlled, regulated life, she will eat her usual of bread and cheese and salad and fruit. But not much cheese.
Ruth Rendell's latest novel, 'Harm Done', is published by Hutchinson, price pounds 16.99Reuse content