'Oh, you're punctual – how very unusual," says Deborah Cavendish (AKA the Dowager Duchess of Devonshire) as she enters the drawing room. I'm not sure whether I'm being congratulated or castigated; either way, I feel she has the advantage, one she never loses. I was already nervous about this encounter. The duchess has just published her memoirs, and journalists are not spared. She describes how, after she had talked about the deaths of four close friends in the second world war, a particularly dumb interviewer asked her, "So, did the war change you?" She also says in the book that you should never believe anything you read in newspapers. As well as representing the dodgy fourth estate, I'm also wondering whether I'm supposed to call her Your Grace.
The duchess says she embarked on her memoirs because she felt her family, and her parents in particular, had been portrayed unfairly in the media, with journalists working from ancient press cuttings. At 90, she wanted to put her version of her upbringing on record. And what an upbringing it was. Debo, as she is called by people who eschew titled formalities, is the last surviving member of the six Mitford sisters, an afterthought (or so she implies in the book), dismissed because her parents had wanted a second son, patronised by her glittering sister Nancy, overshadowed by the fame (or notoriety) of Jessica, Diana and Unity. Her memoir – called Wait For Me! because she says she was always running to catch up with her older, longer-legged siblings – is a touching, funny memorial to a vanished age of debutantes, balls and young men with fancy titles making the ultimate sacrifice on the battlefield. She only started to write in her 60s – first about the ancestral seat of Chatsworth, then more generally – but belatedly she is catching her writerly sisters up.
Her life has been remarkable, and only her languid, laconic, matter-of-fact style allows her to shoehorn it into 370 pages. There is enough here for a dozen books. She must be one of the few people to have met both Adolf Hitler and John Kennedy, has been a familiar of the Queen for her entire reign, and was related by marriage to Harold Macmillan and used to go shooting with him. "When he became prime minister [in 1957, having previously been chancellor]," she tells me apropos of nothing in particular, "he told me it was wonderful because at last he had time to read." She laughs. Her sense of humour and recognition of the absurdities of life are apparent throughout both her book and our conversation, bearing out her friend Alan Bennett's remark: "Deborah Devonshire is not someone to whom one can say, 'Joking apart . . .' Joking never is apart: with her it's of the essence, even at the most serious and indeed saddest moments."
She may have deemed my punctuality worthy of remark because she lives in the middle of nowhere, in a hamlet called Edensor on the Chatsworth estate in Derbyshire. The duchess occupied Chatsworth itself, perhaps England's finest country house, until the death of the 11th duke in 2004. Soon afterwards she moved about a mile away, to a vicarage on the edge of the estate, far enough from the house to give her son Stoker (nicknames are important in these circles – his real name is Peregrine), the 12th duke, and his wife Amanda, the new duchess, room to breathe. Dowagers have to know their place, and recognise their moment in the sun has passed. Nothing, she emphasises, belongs to the person; it all goes with the title. "I've lived in furnished rooms all my life since I was married."
Her final set of rooms are in the Old Vicarage at Edensor, which she occupies with her butler Henry, who has been with the Devonshires for almost 50 years, an ultra-efficient secretary called Helen, who has been with her for almost 25, and large numbers of chickens, pictured on the cover of her book. She enumerates the several breeds she keeps, and seems a little disappointed that I am unaware of the differences. Another dumb journalist who will probably confuse a Derbyshire redcap with a Scots dumpy.
We talk in the drawing room, silent save for the ticking of the clock on the mantelpiece. Her piercing blue eyes unnerve me, though she tells me towards the end that, because of macular degeneration, she can barely make out my face. That also makes reading virtually impossible, and it is remarkable that she has managed to write this book, scribbled in bed early in the mornings ("I wake up very early – I love the shipping forecast at 5.20"), with Helen typing it up. Her hair is steely grey and voluminous; she is elegantly dressed in high-necked blouse, lemon cardigan and sensible skirt; on her left wrist, beside her watch, she has a band with a small red disc that I mistake for a bracelet; she tells me it is an alarm in case she has a fall, but that she likes to pretend the red button she has to activate is a ruby.
I begin by asking her to recount her meeting with Hitler in 1937, when she, her mother and her sister Unity (who was besotted with the Führer) took tea with him in Munich. In the book she recalls him noticing they were "grubby" after a journey from Vienna, and showing them to the bathroom, where he had brushes inscribed "AH". She has a passion – and a talent – for details. "I didn't know Hitler," she tells me. "I only went to tea with him once. He was very fond of my sister Unity." She starts recounting the meeting, but soon gets bored. "The story's been told so often I think it's pretty old hat." She would almost certainly rather talk about chickens.
Her sister Unity was an enthusiastic Nazi; her other sister Diana married Sir Oswald Mosley, had extreme views on race, and spent part of the second world war in Holloway prison because she was deemed a threat. I suggest that in her memoir, she is a little kind to both, given their views. "Quite kind?" she says incredulously. "I adored them. I really loved them both. When we got old, I liked Diana better than any other person in the world." So she accepted their politics? "Their politics were nothing to do with me. The same with my sister Jessica." Jessica, who spent most of her adult life in the US and is best known for her book The American Way of Death, was a communist and civil rights campaigner. "She was as outlandish as any of them," says the duchess.
I ask her why the Mitfords have exercised such perennial fascination. "I can't imagine," she says in her very deliberate, almost regal drawl. "I know it sounds stupid to say that, because I realise they were good writers. All Nancy's books are in print again. She would have been amazed at me writing this book because she thought I was completely half-witted. She called me 'Nine' [Debo's supposed mental age], and used to introduce me to her smart French friends long after I was married by saying, 'This is my little sister aged nine.'"
The sisters were educated at home, because their mother didn't believe in exams, and Debo spent most of her time hunting, skating – she was good enough to encourage interest from professional coaches – and going fishing with her father Lord Redesdale, an eccentric who only read one book in his life, Jack London's novel White Fang, and enjoyed it so much he didn't believe it could be bettered. Her father – handsome, fearless, irascible – is the central presence in the book, and no doubt the figure who shaped his dangerous, disputatious daughters. "Farve either liked you or he did not," she writes. "There was no middle way. My mother sometimes tried to reason with him, but reason was not part of his makeup."
The deaths of her friends in war are not the only bereavements in the book. She had three children who died within hours of her giving birth. Her first child, who was born 10 weeks premature, died in 1941, the year in which she had married Andrew Cavendish, second son of the 10th Duke of Devonshire. "It was in the war and people were thinking of other things, so it was skated over by everyone as a fact of life. But it was an awful blow for Andrew and myself. Then there were two more, but for different reasons. They were just a few hours old." How did she cope? "How can you not? You've got to if you're faced with these things. Life had to go on in an ordinary way."
Reawakening the ghosts of her past for the book gave her no pain. "When you are very old, you accept what has happened. You cry over some things, but not a lot. It's too distant. It's as if part of you gets nearer to it yourself, and then you think the churchyard here [in Edensor] is very handy, whereas Andrew [her husband] had to come all the way from Chatsworth. Paddy Leigh Fermor [the writer and one of her greatest friends, now 95] insisted on walking behind his coffin. Well, he won't have very far to walk for me." Lucian Freud, who has painted her on several occasions, is another close friend. "I see him when I go to London and I leave him eggs on the doorstep. He seems to like that. I really love him and I always have."
She realises she is a survivor, but she doesn't want to be seen as an anachronism, and another journalist gets it in the neck for calling her a "lilac relic of bygone days". But as befits a duchess (and someone who has little interest in politics), she proudly proclaims that she has voted Conservative all her life and inveighs against change. She dislikes the modern obsession with health and safety, and mourns the decline of the English language, the destruction of the postal service and the disappearance of Punch. But she accepts modernity is not all bad, welcoming the advances in dentistry. "You've no idea what it was like when we were children," she says. "It was like going to a torture chamber."
Why are you a Conservative, I ask her, which later I think may be a stupid question, given that the Devonshires own Chatsworth, thousands of acres of the Derbyshire countryside, a castle in Ireland, and half a dozen other residences. "I like conserving things," she says circularly. "I like people to stay as they are, though I know they can't." Stumblingly, I point out that at the Guardian we do not wholly approve of dukes, duchesses and other feudal throwbacks. How does she justify them? Her answer is characteristically lateral. "There are two retired head gardeners here," she says, "both of whom have done 50 years at Chatsworth, and they are just such extraordinary people that if you could sit and talk to them you would learn some things that you would never have known. They are just wonderful, and it's really the company of them and the people who work on the farms that I like best of all."
She says time-honoured hierarchies are better than faceless modern conglomerates; the 600 or so people employed at Chatsworth know who they should moan at if things go wrong. "There's always been access to the top here. There's a human. You can laugh at them, you can dislike them, but they're there."
When she married Andrew Cavendish, as the second son he did not expect to become duke, but his older brother was killed in the second world war and he inherited. I am intrigued to know whether at some point the duchess, this regal persona, took over from the real person. "I was very unconscious of it, because I've been a duchess for so long, more than half my life. And now it's become rather unfashionable to have a title of any sort. If you are one, how can you tell how other people feel when they meet one?" What did her sister Jessica, the communist, think of her becoming a duchess? "She thought it was very comical. She takes people as she finds them." I like the way she slips into the present tense when describing a sister who has been dead for 14 years.
We have been talking for more than an hour and I fear she may be tiring. Are you OK to carry on, I ask her? "Yes, very happy," she says, "but haven't you had enough?" I laugh at the way she says this, as if the interview is a boxing match. I learn later from the photographer that she was disappointed I failed to floor her with a killer question, which irks me because I thought I had plucked up the courage to ask one.
In the book, she describes her husband's alcoholism and how that almost ended their marriage in the 80s. But she doesn't mention his infidelities, widely hinted at elsewhere. Was he unfaithful, I ask her? "Oh yes, of course," she says. So why didn't you write about his affairs in the book? "It wasn't my aim to write about them," she says. "People are so odd in England about marriage and what it means. It's not something I would dream of writing about, because it seems to happen to everybody, so what of it? Sex and money are all that interest the press." She describes her memoir as "an antidote to Lord Mandelson's" – a book born of loyalty and love.
I don't get a strong sense of her husband in the book, and ask her to describe him. "He was quick and funny and sharp as a razor, and had great love for his friends. He may have been difficult at times, but he was never boring." Not being boring is important to her. A dull marriage would be unthinkable. "You know how you can't listen to someone who is very dull?" she says. "At least I can't." Now my terror is complete. I know I am boring her. "I love you being terrified," she says. "That's so funny."
She would probably go on all afternoon, but we get into a dispute about the date of the Countryside Alliance march in London and consult her secretary, so the drawing-room door is opened and the world intrudes. The contest is over, and I have been soundly defeated by this 90-year-old who retains the grace on the ice she had as a child. She asks Henry to offer me drinks. I hear her telling him he needn't put his jacket on to serve them, but he insists on doing so, not wishing to change the habits of a lifetime. He is about to retire, but will stay on for two days a week at the dowager's request. Not, I suspect, because she needs a butler, but because she is so attached to him as a person. People. Those tricky things that get in the way of political theories. Yes, we must sweep away centuries of privilege, but I do hope Henry, Debo and her chickens survive.
Wait For Me!, by the Duchess of Devonshire, is published by John Murray (rrp £20). To order a copy for £17.99 with free UK p&p go to guardian.co.uk/bookshop or call 0330 333 6846.
