US Edition In June 1937, Deborah Mitford visited Munich where she took tea with Adolf Hitler. 'I went with my sister Unity and our mother to his flat,' she recalls. 'The atmosphere was rather awkward because neither my mother nor I could speak German. Unity and Hitler talked away while we sat there not being able to understand what they were saying.
'But one or two odd things happened at that tea. My mother and I were quite dirty because we'd come in an open car from Austria, so we went to wash in his bathroom. Hitler's towels, I remember, had "A.H." embroidered on them. I've always thought that was so strange, so unlike what you would expect of someone like that. I remember, too, that he rang a bell several times and no one came. That was a bit odd, too.'
Yet what seems oddest of all in retrospect is how little impression the occasion made on her. In a letter to her sister, Jessica, Deborah barely mentioned it, being far more interested in describing a café violinist whom she had fallen for. 'Well, I've never been very interested in politics, you see,' she says, laughing. 'And the truth is that I didn't give it much thought. If you sat in a room with Churchill you were aware of this tremendous charisma. Kennedy had it too. But Hitler didn't - not to me anyway.'
Deborah Mitford is the last of the Mitford sisters. All her five siblings have died, as has her husband, Andrew, the former Duke of Devonshire. But at 87, Deborah hums with vivacity, a slim, immaculately coiffed woman with bright blue eyes. You don't have to look hard to see why she was hailed as a famous beauty. Today she is wearing a blue shirt with a white collar. 'It's my district nurse look,' she says, an effect offset by a jewelled spider pinned to her left-hand collar which looks as if it might crawl up her throat at any moment.
She is sitting in a studio in the garden of the former vicarage she moved into when she left nearby Chatsworth 18 months ago. All around her, on steel shelves stretching from floor to ceiling, are files containing letters the Mitford sisters wrote to one another. A selection of these letters, edited by Diana Mitford's daughter-in-law Charlotte Mosley, is just about to be published. It's a book of more than 800 pages, but it represents just five per cent of the letters the sisters exchanged. They wrote to one another almost every day, and sometimes more than once, a correspondence that lasted from the 1920s until 2003, when Diana died.
'I still go on writing to Diana in my head because she is the person I had a particular affinity with. We understood what one another thought before we thought it.'
People who have met Deborah Mitford have often remarked on the way she talks. How she says 'lorst' for 'lost' and 'gorne' for 'gone'. Indeed, to read some descriptions you would think she could scarcely utter a vowel without becoming marooned on top of it for several weeks. But what seems more striking is the contrast between the way she speaks and the way she writes. In conversation, she expresses herself with great economy and clarity, albeit punctuated by sudden bursts of flattery - 'You are so right!' 'Absolutely spot-on!' Yet to read the sisters' letters is to be plunged into a torrent of gushing adjectives, underlinings and elaborate nicknames. While Unity may have been the champion gusher here - 'The Führer was heavenly,' she writes at one point - Deborah doesn't lag far behind. In a letter to Diana in prison - along with her husband, Oswald Mosley, Diana was locked up for being a Nazi sympathiser - Deborah wrote, 'I do so long to see your cell.'
The youngest of the Mitford girls, Deborah was brought up at the family home in the Cotswold village of Swinbrook until she was 16. While her sisters couldn't stand the place, Deborah loved it and was devastated when the family moved out. Almost 40 years later, in 1971, Deborah wrote to Nancy, 'It broke my heart. Nothing had ever taken its place and nothing ever will … Worse than anything that has happened since, the loss of three babies, my four greatest friends being killed in the war - nothing has saddened me like the going from Swinbrook.'
'Did I write that?' she says now, her eyes widening in surprise. 'That was going very far. But I think there was a sense that it was the end of childhood for me. An air of harmony prevailed at Swinbrook that didn't prevail afterwards.'
A year later, Jessica Mitford [Decca] - two and a half years older than Deborah - caused a scandal by eloping to Spain with Esmond Romilly. The couple subsequently married, but Romilly was killed in action in 1941. Up to this point, the two youngest Mitfords had been particularly close, but there's a sense that their relationship never fully recovered from the shock and betrayal Deborah felt at the time.
'I think that's true. It nearly did, but not quite. One of the reasons was that Esmond Romilly so hated all of us - and possibly me and Bobo [Unity] above all because we were so close to Decca. I think he saw me as an extra horror. And I really couldn't stand him,' she says with uncharacteristic venom. 'He was one of those people who's electric, of whom I've seen several in my life. But he was electric in a horrible way. Everything seemed so negative. He was dishonest, a liar, all those things … But of course Decca absolutely adored him and it was the great tragedy of her life that he was killed.'
The great irony here, given Deborah's feelings towards Romilly, is that the Daily Express reported that he had run off with her, not Jessica. As a result, the paper had to pay Deborah £1,000 for 'compromising her prospects of marriage'.
'That really was one of the best things that had ever happened to me. Just wonderful: £1,000 was a huge sum of money in those days.'
Did she feel that her marriage prospects had been compromised?
'Oh, I don't think I considered that very much.'
At almost the same time as Jessica eloped with Romilly, Diana Mitford married Sir Oswald Mosley, leader of the British Union of Fascists. They married in Goebbels's living-room with Hitler in attendance - Hitler, with a typically immodest flourish, gave the couple a signed photograph of himself as a wedding present.
Meanwhile Unity had become hopelessly infatuated with Nazism in general and Hitler in particular. While Deborah does not seek to excuse what Unity did, she clearly hopes that publication of the letters might make people see her in a more sympathetic light.
'She had such qualities: she was totally truthful, totally loyal and she could be very funny. Physically, she was beautiful in a funny sort of way. Everything was too big. She had the most enormous navy-blue eyes, an absolutely straight nose and very bad teeth because she had lived on mashed potato for a year and a half when she was a child. But she was just taken over by this fascination for Germany and all that went with it. I think she had this tremendous naivety which turned into ideological commitment.'
On the day war broke out, Unity tried to commit suicide by shooting herself in the head. She survived, but only just. Hitler arranged for her to be taken to a hospital in Switzerland where Deborah and her mother went to collect her.
'It was an absolute nightmare. We caught the train from Calais to Bern. I can remember the shock of seeing her very clearly. She had lain unconscious for weeks and the bullet was still inside her. Her hair was completely matted and she couldn't bear anyone to touch her head. It was as if she had become an enormous child. The journey back was terrible. Every time the train stopped suddenly, she was in agony.'
Severely brain-damaged as a result, Unity needed constant care - she died nine years later, in 1948. 'I don't think there was ever any realistic expectation that she would make a recovery. The bullet had destroyed quite a lot of the brain. Afterwards, she developed these enthusiasms for various religions. Like her old enthusiasm, but not so violent, of course. She was a Christian Scientist, then a Roman Catholic … everything that came along."
Nine months after the outbreak of war, in June 1940, Diana and Oswald Mosley were interned. They would almost certainly have been locked up anyway, but their cause wasn't helped by Nancy Mitford telling an official at the Foreign Office that she thought her sister was 'an extremely dangerous person'. Diana did not discover this until 10 years after Nancy's death.
Does Deborah think that Diana would ever have been able to forgive Nancy if she had known?
She gives a long sigh. 'I wonder … They adored each other underneath, but I just don't know.'
When Diana was in Holloway Prison, Deborah would visit her every few weeks. 'She was allowed visitors for half an hour a fortnight. Most of the time she saw her children, but my mother and I used to go sometimes. I did long to see her cell, but instead we saw her in this filthy, dirty, visitors' room with a wardress always there. Diana absolutely adored one wardress who became a great friend. But the others weren't so easy. I don't know if they picked on her. She was certainly an outstanding figure there, so they might have done.'
With one sister imprisoned for being a Nazi sympathiser and another who was so besotted with Hitler that she shot herself, one might assume that some stigma would have stuck to the Mitford name during the war. Deborah, though, insists that she was never aware of any. 'I mean, I'm sure there must have been, but I certainly never lost any friends as a result. They were just very sad for all the horrible things that had happened.'
'What did you think of Oswald Mosley?'
'Oh, I loved him,' she says without hesitation. 'He was very ready to be amused and to laugh at whatever was going on. And he had these now non-existent, old-fashioned good manners - just like Uncle Harold [Harold Macmillan]. In fact, I remember a dance here at Chatsworth, not so long after the war. Sir Oswald was here and so was Uncle Harold. At the time there were one or two people who were not prepared to meet Sir Oswald. But Uncle Harold, who of course had been an old adversary, took him by the arm and together they walked round the whole house together. I've always thought that was a very nice thing to have done.'
Throughout her life - but especially when she was young - Deborah passed herself off as being less intelligent than her sisters. Not that everyone was convinced; Diana believed that while most people pretend to have read books that they haven't, Deborah pretended not to have read books that she had.
This diffidence - and her lack of interest in politics - marked her out as a natural peace-keeper in the family. By the mid-1940s, there was plenty of peace-keeping to be done. Her parents had separated, partly as a result of the strain of looking after Unity, while Jessica and Diana were estranged, owing to political differences - Jessica became a member of the American Communist Party in 1944.
'It wasn't a role I particularly sought. But I have always hated rows, and there were heaps of them. I used to try to stop them. Very priggish of me, I suppose.'
Why priggish? 'Well,' she says wafting a hand. 'Just trying to stop things from happening.'
As for Nancy, the oldest Mitford sister, her personal fortunes ran in a diametrically opposite direction to her professional ones. A successful novelist and historian, she fell hopelessly in love with a very ugly yet unstintingly unfaithful Frenchman called Gaston Palewski. 'He was a complete wastrel, really. Very charming, but you'd rather die than say you found him prepossessing.'
Deborah herself was luckier in love. In 1941 she had married Andrew Cavendish - he became the Duke of Devonshire when his father died in 1950. Marriage also brought her very close to the Kennedy family. 'I knew Jack as a teenager because his parents lived round the corner when his father was the ambassador in London. He was a sort of dancing partner of mine. Then Andrew's brother married his sister, Kick [Kathleen]. And then Jack suddenly became President. He was the only politician I have ever known, and I've known quite a lot, who could laugh at himself. And he did - loudly. That was so attractive.'
She attended Kennedy's inauguration in 1961, then saw a good deal of him a few months later when an exhibition of drawings from Chatsworth was put on in Washington. 'He came to the opening of the exhibition. Everyone was amazed, especially me. Apart from anything else, it was right in the middle of the Cuban missile crisis. Besides,' she adds drily, 'museums weren't exactly Jack's line. I don't think he'd ever set foot in the place before.'
When Andrew's father died, he and Deborah inherited Chatsworth, with its 175 rooms, 21 kitchens and 17 staircases. Together, they did the house up and transformed it into a hugely successful business - it took them 24 years just to clear the death duties incurred by the estate.
Eighteen months ago, after Andrew's death, she moved out so that their son, Peregrine, could take over the house. How did she feel leaving Chatsworth? 'Odd. That's really the best word to describe it. But it was high time for a change there, and for me. I'd been there for almost 50 years and I was getting jolly old. Fortunately, I had this lovely house to move into, and I can say quite honestly that I adore it here.'
'You are the last Mitford sister.'
'Yes.'
'Is that a very lonely feeling?'
'Well, when Diana died it was. Awful … and as I say, I still mentally write letters to her. But you know life goes on. I'm so lucky with my children and grandchildren - I've got 15 great-grandchildren - so there's plenty on, if you know what I mean.'
In the Dowager Duchess's downstairs lavatory there is a large poster of Elvis Presley gazing down from the shiny silver-papered wall. There are other bits of Elvis memorabilia dotted round the house, too - photographs, a roll of cloth with his image printed on it. Deborah may not have discovered Elvis until she was in her sixties, but once smitten there was no holding her back - another symptom, perhaps, of the Mitford sisters' tendency towards hero-worship.
'I turned on the telly one day and there was a programme about him. Suddenly, I saw genius - simple as that. I've been to Graceland twice, you know. Wonderful place; I can't recommend it highly enough.'
If she could choose to have tea with either Elvis or Hitler, which would it be? She looks at me in astonishment. 'Elvis, of course. What an extraordinary question.'
It's time for her to go back to her house and be photographed. But rain has started lashing down outside, so hard that it's pock-marking the lawn. I suggest we stay where we are until the rain has eased off. Deborah is having none of it. 'Why don't we run?' she suggests. And run she does, bounding across the wet grass in great scissoring strides.
'The Mitfords: Letters Between Six Sisters', ed Charlotte Mosley (Fourth Estate), is available for £23 plus £1.25 p&p from Telegraph Books (0870 428 4115; www.books.telegraph.co.uk)