Marje Proops is going through her letters with her assistant, Emma Field. She reads them with a kind of ardent attention, her face lighting up, hands gesticulating. Her office on the fourth floor of the Daily Mirror building is smaller and less lavish than might be expected of the journalist who is undoubtedly - no contest - the doyenne of Fleet Street; but then Marje is a genuinely modest woman.

She joined the Mirror as a fashion artist in the Forties; then became fashion editor; then a columnist. Today, she is much more to the paper than its agony aunt - although she does that job with compassion and common sense - she is its symbol of continuity, rising above the mayhem caused by proprietorial scandal or editorial misjudgement. She was on the board of directors until four years ago, when her husband, 'Proopsie', warned her that Robert Maxwell was up to no good, and advised her to resign.

Every week her page counsels the paper's eight million readers on health, money, debt, legal or any other problems. Last week she was replying to a 19-year-old, terrified that his mother might find out that he masturbated. 'He's typical of my young male readers. Oh yes] I still get letters asking whether hair will grow on the palms of their hands, or their penises will drop off or their sexual organs be permanently damaged if they masturbate. Sex education in our schools is just not good enough.' This week, a mother writes to say she has just discovered that her son- in-law is bisexual and is having an affair with his bisexual boss. 'The mother is alarmed, a) because of the fear of Aids, and b) because she thinks it may spell the end of her daughter's marriage. By putting that letter in the paper I reach a lot of other people who can relate to those fears.'

Marjorie Proops was born Rebecca Rayle around the time of the First World War, and spent her first months above a greengrocer's shop in Woking. Then her father took on a pub in Hoxton, one of the toughest areas of east London. One of her earliest memories is of being called 'Becky the Jew- girl' when she was only four or five years old. She ran home crying to her mother, who said, 'Lucky you've got another name', and from then on she was known by her second name, Marjorie, so- called after the willowy, blue-eyed, blonde heroine of the book her mother had been reading when she was born. The new Marjorie longed to be willowy, blue-eyed and blonde, too; or at any rate, as pretty as her sister, Josephine.

She married 'Proopsie' because, she says, he was the first man who didn't drop her as soon as he laid eyes on her sister. They met when she was 17 and he proposed four days later. Having first checked that he was a Labour voter, she warned him that she intended to be a career woman so if he wanted a little domestic helpmeet, he could forget it. 'I was a bit before my time with those attitudes, but my mother always impressed upon me and my sister that a woman should be able to look after herself.' Luckily for the Mirror and more than a million agony correspondents so far, Proopsie was prepared to tolerate a working wife. 'He was very, very supportive at a period in our society when it was not on for a middle-class Jewish girl to go out to work.' Proopsie died three years ago. She misses him dreadfully.

Her entire working life, apart from a brief fling with the old Daily Herald, has been spent on the Mirror, and she became its agony aunt in 1954. The current editor, Richard Stott, has just devoted several pages to celebrating 40 years of Dear Marje. 'Dictatorial editors,' she says drily, 'can interfere with the calendar a bit.'

Have readers' letters changed in those 38 years? 'When I began as a columnist women didn't write to complain about not getting six orgasms a night: they didn't write about orgasms at all. But people don't change, basically, and the problems were not very different. I have always heard about mother-in-law problems, step-child problems, unfaithful husbands - though I think in the early days there were fewer unfaithful wives.

'A constant complaint that I had from women years ago was that the man would never say, 'I love you.' I assume they thought it was sissy. But today more young men are open about their emotions and do talk, although the fact that the words for the human body and sex are swear words denotes the poverty of the language of love, and prevents some people from using them at all.

'The Mirror is one of the few papers left that still cares what happens to its readers. It acts as a sort of unpaid social-worker-cum- adviser to the nation,' she says. 'Every letter that comes in addressed to me is registered, logged and has a number attached to it. Very often the inquiries turn into long-term cases. All that takes a lot of administration and costs a great deal of money, with no return other than goodwill. My page has a staff of nine - including me and Eddie, my driver.'

The driver is no luxury: she had her first hip replacement 14 years ago and since then there's been another. Despite that she is now quite badly handicapped by arthritis and has to lean on her assistant, Emma, as she walks. 'Emma's the daughter I never had,' Marje says wistfully. A hysterectomy after the birth of her son, Robert, put paid to any hopes of more children.

Has her view of men - or indeed, of human nature in general - been soured by reading every day about extremes of brutality? 'No, because it's very dangerous to generalise about people. I wouldn't denounce the entire male sex as brutal. There are some unspeakable men out there, but also some unspeakable women who goad men to the point where they take action which, though inexcusable, is understandable. Men react violently; women react spitefully.

'I would be astonished if any one of the men I work with here had ever tapped his wife in anger, so I can't look at the men I meet every day and think, you're a lot of sodding bastards who go home and beat up your wives or girlfriends. Most men are perfectly decent and civilised. On the other hand, if I went to a few pubs in London or Birmingham or Liverpool or Glasgow I'd encounter a lot of men who would send shivers down my spine.'

Her last remarks are surprising, seeming to imply that salaried, suited, middle-class men like Marje Proops's colleagues don't beat up their wives. She says this is not what she meant. 'Violence in marriage is often due to alcoholism, and that is found in just as many middle- and upper-class people and gentry as those who swig away their pints in pubs.'

Does she see any connection between the abuse and violence that her readers suffer and the explicit crudity of today's tabloids? 'I don't agree that all the tabloids are brash and vulgar all the time, though all of them are some of the time. It's to do with changes in society and the law, but is caused very largely by television and the cinema. The fact is that you zap on the television and you've got naked couples humping each other and panting away, and their language is much more explicit. I'm not being critical when I say this. I don't set myself up as a moraliser. But all these threads reflect rather than lead public opinion.

'We are in a hugely competitive business against the other tabloids. We have to get readers and keep them, and the figures seem to show that what the readers want is ever sexier and more intrusive. If all the tabloid editors sat round a table together . . . Kelvin (MacKenzie, of the Sun), Stotty (Richard Stott, of the Daily Mirror), Nick Lloyd (Sir Nicholas, of the Daily Express), the lot . . . and said, right-ho, boys, gentleman's agreement: less dirt, sex, and showbusiness; more politics and news in the paper - then half the circulation would disappear overnight. In a free society, people can choose what they want to buy, and long may it last] If you're running a newspaper, you put in the pages that people are interested in: which for a large number of people appears to be . . . sex, showbusiness, the telly, nudity, cabinet ministers knocking off actresses and royal marriages going dramatically awry.

'If that's what they want to read about, I think we should give it to them, or else they won't read at all. As it is, we can slide in among all that stuff the odd paragraph about news or important issues. The Mirror has Paul Foot, for instance, who's a great campaigning journalist, and we have good, thoughtful leaders - unlike the other tabloids. But if you flood the paper with important stories about moral issues people will simply turn the page and not read it. I don't deplore the paper today. I've served under 10 or 12 editors, each of whom changes it a bit, but for me it remains basically the Daily Mirror I joined.'

Are the readers also still basically the same as those she was hearing from nearly 40 years ago? 'One of the most dramatic changes I have seen has been in women's perception of themselves. I'm a very vigorous feminist and I know we have influenced both the law and attitudes. We may have been a bra-burning joke, but young women today are at the receiving end of the benefits of our noisy demands for equality. But feminism has also unleashed in some men a fear and hatred of women. I have always worried about that backlash. Despite the fact that a lot of men benefit considerably, especially in these harsh economic times, I get a lot of whingeing letters from men stuck at home running the household because their business has gone down, while their wives are still working as teachers or nurses. But I do understand that such men find it difficult to accept the role reversal. They were brought up to be serviced by women.'

Does Marje - who must in her lifetime have seen more problems than most people's imagination could encompass - believe that violence and sexual abuse have increased; or are we simply better- informed about what goes on? 'I think all that's changed is that we know more about it. Those problems always existed, and not just in working-class families. If you study Victorian social history (I've just been reading a book about it) you'll know that brutality and deprivation were ten times worse in Victorian London than they are today. And nobody was doing anything about it in those days.

'I think people always had the same kind of sexual drives. There's a tremendous element of sado-masochism in the relationships that readers write to me about. I get letters describing the most horrendous cruelty and appalling sexual practices; and yet these women remain with the men who inflict these awful punishments, although it seems to me in many cases that they could leave. Some women are trapped, and I have to say: try to find a women's aid shelter - even though I know some of them are like dog kennels. The conditions are so appalling that some women prefer to go back to the men from whom they had escaped, rather than stay there. But at the same time there are a lot of women who're perfectly happy to be victims. There's often a sexual element in it. I hate the word 'submit' more than any other in the language.'

Marje Proops gets between five and six hundred letters a week, most expressing feelings of pain. Is she burdened by the knowledge of this pain, often expressed in anonymous letters by people terrified of discovery?

'I often wake up in the night or first thing in the morning, worrying about a particular problem. I have a number of little escape routes. I go to bed quite early, now that I am by myself, and read - mostly biographies. I watch a lot of telly. I'm a dedicated soccer fan. I play bridge. I have my cat, Fred.' (She shows me his photograph: a short-haired British Blue with a pleased expression.)

She must be recognised in public? She sighs. 'Yes. People try to tell me their troubles on the streets, in shops, everywhere. I say, 'It's not a very good time to talk about it. Could you possibly drop me a line so that I can think how best to advise you?'

'The hardest part of my job is that there is no solution to the vast majority of problems. As I go through the letters I sigh with frustration and despair that I cannot solve people's problems; but often - no, almost always - there is no solution.'

Marje Proops works nine hours a day, five days a week, and takes work home at weekends. I haven't asked her age, but she must be in her late seventies. Does she have any plans for retirement, so that she can shed this burden which clearly oppresses her? 'No,' she answers. 'I shall go on for as long as I'm needed. I shall die working.' Fresh-faced, bright-eyed Emma, 'my human crutch', comes in to help her down to the executives' dining room. On the way Marje greets, by name, every single person she passes.

I once read, in a short story, about a Welsh death-bed custom. Until only a generation or two ago, poor and hungry men would roam Wales looking for the recently dead. A banquet would be prepared and spread out on the chest of the corpse. The sin-eater would consume it, and with it, the sins of the dead man. He would leave the house heavier by the weight of a meal and another man's sins. Marje Proops is a kind of sin-eater for our times.

(Photograph omitted)