The two faces of Diana Mosley the indestructible

Her own gifts as a writer were overshadowed by her sisters. Laura Thompson rates her second only to Nancy

Earlier this year, I took part in a books programme on the radio during which we discussed A Life of Contrasts, the autobiography of Diana Mosley. Asked for my opinion of the book I gave it honestly, saying that I thought it intensely fascinating to read the life of such a woman, especially when it was so well written. I went on to mention that I had visited Diana the previous year, when she invited me to her Paris flat to chat about her sister, Nancy Mitford, whose biography I was then writing. She was, I said, immensely kind to me and undoubtedly the most charming person I had ever met.

At which point I realised that I had forgotten myself. I had forgotten, too, the orthodoxies and hypocrisies which for the past 60 years have said that Diana Mosley can be talked about ad infinitum - as indeed she has been, all this week, since her death was announced on Tuesday - so long as the talk is punctuated by constant reminders of what a dreadful woman she was.

The presenter of the radio programme turned her head from me with a shudder, and pronounced what was clearly deemed to be the final, necessary word about A Life of Contrasts: that however charming it might be, it was also a repellent book. I was left sounding like a bit of an idiot, if not a downright Fascist sympathiser, for having dared to take pleasure from either the company or the prose style of the wicked wife of Sir Oswald Mosley.

I found this very annoying at the time. Yet I have to admit that the presenter had absolutely identified the conundrum of Diana: she was charming and she was repellent, and nobody has ever been able to reconcile the two sides of her. Certainly her own book does not. This may be what makes it so interesting to read, as well as so easy to condemn: it has all the opacity of her remarkable personality.

For example, she writes about her first meetings with Mosley in the early 1930s, when she was a beautiful young woman with an easy life, a rich husband and two young sons, and when she decided to leave her family, tear her reputation to shreds and set herself up as a married man's maîtresse en titre. She describes Mosley's political views and the way he expressed them, then says, quite simply: "Of course I fell in love with him, and decided to throw in my lot with him..." This is an extraordinary way of addressing this truly mysterious act. Clearly she felt that there was nothing more that needed to be said, or that could be said.

She also, let it be remembered, was a Mitford, and most Mitfords like to tease: no doubt she knew the effect of her remorseless refusal ever to atone for her fascination with Mosley, Fascism or Nazi Germany. No doubt she was immensely amused by the procession of journalists who tripped eagerly into her beautiful flat in the Rue de l'Université to see if she would start apologising for her life. She would have been exquisitely polite to them, they would have fallen helplessly sous le charme and then they would have gone away to clear their heads and stick the knife in. She would have understood it all, and I doubt she would have cared about any of it. She utterly embodied the quality she extols in A Life of Contrasts, that of having "a complete disdain for public opinion". Although that, too, was a bit of a game, since she continually put herself into situations where public opinion would be invited; not least by publishing an autobiography which described how, "in certain moods", Hitler "could be very funny; he did imitations of marvellous drollery..."

Diana also wrote a book about the Duchess of Windsor, and a collection of pen portraits called Loved Ones. Her great gift as a writer seems to me to have been her innate honesty, which sat alongside this equally innate opacity: she was always as faithful as possible to her own view of the truth, even if that view was in itself somewhat occluded. Her writing carries a good deal of her own essence, although it does not perhaps convey how much fun she was. For example, I remember how, during our long chat, she described to me a home owned by some friends in the south of France, whose nearby beach was littered with rubbish and excrement: "One didn't feel awfully inclined to go into the sea." When I transcribed those words they had read very much like the controlled, ladylike, accurate prose of her books; yet I had fallen about laughing when they were said to me, because they had sparkled so vividly with Mitford merriment.

The last surviving sister, Deborah, Duchess of Devonshire, said to me that she thought Diana was "the best writer of any of us": this opinion interested me greatly, but I beg leave to disagree with it (as, I think, Diana herself would have done). Nancy was not just the best but the only real writer among the Mitfords. She was the supreme architect of the Mitford myth; she made writing her life; indeed she was - or became - an artist. There are sentences in her books that could have been written by nobody but Nancy, and certainly not by Diana.

For Diana, writing was just a part - and a partial record - of an extraordinarily long and full existence. "I've had a fantastic life," she said to me, in a manner both matter-of-fact and joyful; Nancy's life was emotionally impoverished by comparison, but through her extraordinarily powerful imagination - through her ability to live, as it were, in the world of her books - she created a reality of happiness for herself. Diana made this point in one of the last things that she wrote: a review of my biography which was also, and entrancingly, a little memoir of her sister. "We had such fun, laughing together. Even now, 30 years after her death, I miss her when something amusing happens."

It is all, now, nearly gone: the sound of that laughter is almost vanished. No doubt many people think that this is a good thing, that the air is clearer for it. For myself, I find the world greyer and duller. After my biography of Nancy was published, Diana wrote me a letter to say how much she had liked the book, and to invite me to lunch with her in Paris; I had to go into hospital and couldn't. Then, last week, I was on the point of writing to her to ask if I might visit in the autumn. It hasn't occurred to me to think that it might be better to go sooner rather than later; I had somehow thought of her as indestructible, a beautiful and eternal monolith.

I shall always regret not making that second visit. And if saying so reflects badly on me, is mal vu by the adherents to orthodoxies and hypocrisies, then I shall do as Diana would have done: I shall not much care.

Laura Thompson's biography of Nancy Mitford, 'Life in a Cold Climate', is published by Review (£20). 'A Life of Contrasts' by Diana Mosley is published by Gibson Square (£8.99). In September, Gibson Square republishes Diana Mosley's 'The Duchess of Windsor', and will publish 'The Collected Diana Mosley', a selection of columns, articles and interviews, in February 2004