Those Wild Wyndhams: Three Sisters at the Heart of Power by Claudia Renton – review

Those Wild Wyndhams is a magnificent first book by the historian and barrister Claudia Renton. It is the startlingly intimate portrait of three sisters who were at the centre of cultural and political life in late Victorian and Edwardian Britain. This description, together with the unnecessarily florid gold writing on the cover, may imply an entertaining romp. In fact it's something far more profound. Renton's book has the wisdom, excitement and psychological depth of a very good novel. She succeeds in the difficult feat of combining the novelist's art with the historian's craft, laying her sources and workings before us.

HarperCollins is marketing Mary, Madeline and Pamela Wyndham as the successors to Amanda Foreman's Georgiana Cavendish, and certainly they were as beautiful, influential and aristocratic as the 18th-century duchess. The Wyndhams counted Henry James, Oscar Wilde and Edward Burne-Jones among their friends. They were painted by John Singer Sargent (the portrait was hailed by the Times as "the greatest picture of modern times"). Mary was the lover of a prime minister and Pamela of the foreign secretary who led the country into the first world war.

However, these women were considerably more likable than the ambitious, gambling Georgiana. The book's appeal lies both in how well we come to know the Wyndham sisters and how enjoyable they are to know. These are women who lived in castles, who had retinues of servants and who, depending on your point of view, might be distasteful in their privilege or alluring in their finery. But they are most compelling not in their frenzied socialising or political manoeuvring but in their complex negotiations between head and heart. All three attempted to live both well and fully, balancing the competing claims of kindness and passion.

The real heroine of the book is the oldest sister, Mary, who was less beautiful and self-important than Pamela (the sister most like Georgiana) and more restless than the happily married Madeline. A tomboy as a child, aged nine Mary was keeping up with the hounds. Aged 17, she fell in love with Arthur Balfour, the future prime minister. Tall, dark and witty, the 31-year-old Balfour was a practised though somewhat hapless womaniser, of whom Gladstone's daughter said ruefully "he has but to smile and women and men fall prone at his feet".

Balfour was unmarried but was too frightened and too slow for Mary Wyndham. By the time he recognised his love for her, she had married Hugo, Lord Elcho, a feckless gambler and a flirt. The marriage was unhappy and both Mary and Balfour regretted their missed opportunity. "You were the only man I wanted for my husband and it's a great compliment to you!" she later told him, "but you wouldn't give me a chance of showing you… and you were afraid, afraid, afraid!"

Luckily for Balfour, Mary and Hugo belonged to "the Souls", a group of powerful aristocrats attempting to live beautifully by dedicating themselves to art, learning and sexual equality. A generation of women brought up with chaperones now sat talking to men in their bedrooms about ethics and art. After one "ethical luncheon", Mary reported that she argued "about the word implied & implicit till 1 o'clock and then couldn't sleep from excitement".

All this intellectual fervour was partly a mode of channelling repressed sexual energy. The Souls were more emotionally than sexually promiscuous, at least in theory; their love affairs were courtly rather than consummated. Nonetheless there was a possibility for intimacy that enabled Mary and Balfour to maintain an immensely sustaining public alliance. When Mary's three-year-old son, Colin, died from scarlet fever, it was Balfour who comforted her, assuring her of the perfection of her bond with her child.

However, Balfour, though supportive, was rarely demonstrative, dismissing verbal compliments as "impossible". As a result, Mary allowed herself to be seduced and impregnated by her cousin, the poet Wilfrid Scawen Blunt, once the lover of her mother, while visiting him in the desert. Mary confessed the liaison with Blunt to her husband and her lover, briefly rupturing both relationships. However, her new-found sexual liberation quickly extended to her love affair. By the time that Balfour became prime minister in 1902, his relationship with Mary was sexual and she played a crucial role in advising him on policy and appointments. Partly as a result of her influence, Balfour filled his cabinet with Souls. The world recognised Mary's new eminence; she was granted a two-hour tete-a-tete with the kaiser in Berlin. Renton points out that it's telling that neither Mary nor her sisters supported female suffrage. They did not need to, given that they had more influence than most of the men of their day.

In the end, Renton's portrait of the three Wyndhams suggests that they were more sad than wild. The daily letters they wrote to friends, lovers and relations make them a gift for the biographer, but Renton resists the temptation to let them speak solely for themselves. "One has to delve deeper… to discover the fault lines and shadows that exist in any family," she tells us. This is what she has done, astutely and subtly, allowing the tragedy of the story to be laid bare.

The lives of the whole Wyndham family were torn apart by the first world war. Two of Mary's sons and one of Pamela's were killed, and Renton tells this part of the story in heartbreaking detail. When Mary accompanied her son, Yvo, on the train that she rightly suspected would lead him to his death, she watched him sleeping and found that beneath the "shallow safety of the moment" was a "haunting dreadful fear, and the vision of him, lying stretched out cold and dead". Renton's novelistic skills are especially on show in this section of the book. She recaptures the anguished doubt of this time by interweaving the increasingly desolate lives of the three sisters in England with the experiences of their sons on the battlefield, where an initial surreal jollity (Yvo compares war to a fairground) gives way to horror.

After Yvo's death, Mary felt as though "all the universe was rocking round one". At a time when her class still attempted to see wartime deaths as noble sacrifices, she insisted to Balfour (now First Lord of the Admiralty) that this was a tragedy: "I will not believe that sadness is not sadness." But still she and her sisters wrested dignity out of old age. At the end of her life Mary walked with two sticks, complaining to Balfour that she felt like "a snarling wrinkled charwoman", but she was described by a friend as still lovely, her eyes shining like those of a young girl "with inexhaustible fun". This was a woman who had loved seriously, constantly but ultimately painfully, and who had managed to live fully while remaining generous and loyal. "I am and always shall be sorry for wounding the feelings of anyone I care for," Mary once told her cousin Blunt, "but otherwise it is difficult to wholly regret days of beauty & romance." The beauty and romance – sometimes joyful, more often wrenchingly sad – are captured unforgettably in Renton's wonderful book.

Lara Feigel is the author of The Love-charm of Bombs: Restless Lives in the Second World War (Bloomsbury)