In 1940, Nancy Mitford helped send her sister, Diana, to prison. Or at least, she tried—the British government probably didn’t need the additional testimony, but she gave it, anyway.
Nancy and Diana were the two eldest of six Mitford daughters—minor, cash-strapped British nobility who arrived on society’s stage in the sparkling, frenetic early 1920s. Both ran with the sharp-witted Bright Young Things; Nancy eventually embarked on a career as a satirical novelist and Diana leveraged her considerable beauty and charm into an immensely successful society marriage, landing the fabulously wealthy Bryan Guinness.
None of this origin story is particularly shocking, nor would it have been enough to spawn the entire cottage publishing industry that exists around their family. But then Diana met Sir Oswald Mosley, leader of the British Union of Fascists, setting into motion a train of events that pit sisters against sisters, and sisters against parents, and their parents against each other. The story of the Mitfords is ultimately a story of aggressively nursed betrayals, both big and small. Nancy’s decision to inform on her sister perfectly illustrates why anybody still buys books about these people: Imagine a Real Housewives franchise where half the cast goes Nazi.
Mosley had begun his political career as a Conservative, before switching to Labour, then leaving to form his own “New Party,” which was walloped in the 1931 election. After the New Party’s overwhelming defeat at the polls, he pivoted to unapologetic, outright fascism. As the right-wing ideology swept across Europe, Mosley was determined to bring the movement to England. Around the same time, Diana decided to leave her husband for Mosley—who was married at the time, with no intention of leaving his wife. She would live openly as his mistress, throwing over one of the most eligible bachelors of the age for a philandering politician who was quickly passing beyond the limits of respectability. Not quickly enough for comfort, though. It would be wrong to assume that he was rejected wholesale the moment he embraced fascism, and many in the British aristocracy were happy to consider the possibility as a bulwark against their bigger fear, Communism.
It wasn’t the only involvement by a Mitford sister with one of the monsters of the age. Around the same time, another Mitford, Unity, spent a fateful year abroad in Germany, managing to charm her way into a personal friendship with Adolf Hitler himself, sort of a pet English fangirl with strikingly Aryan looks and the middle name “Valkyrie.” And often, Diana was right there with her. The pair stayed with Joseph Goebbels during the 1936 Olympics and were sent off in style to the Wagner Festival at Bayreuth in a Mercedes courtesy Hitler. The Third Reich was an obvious ally for the BUF to cultivate, and Diana spent a great deal of time lobbying German officials in a scheme to get a radio license that would allow the BUF to operate a station broadcasting from Germany into the United Kingdom, which was perhaps less about propaganda than the pure money-making opportunity to fund the party’s activities.
When Mosley and Diana decided to marry—after his wife died unexpectedly—the Goebbels helpfully provided their parlor for the ceremony. Hitler attended.
Diana stuck with Mosley after the 1934 Olympia rally, when Blackshirts dragged protestors out of the crowd and beat them; she married him two days after the 1936 Battle of Cable Street, an attempted Blackshirt march through the heavily Jewish East End of London, thwarted by locals who rioted to keep the fascists out. Mosley and the Blackshirts withdrew at the police’s request, but the next week a group Blackshirts went on an East End rampage, attacking Jews.
Diana’s connection with Mosley drew many of the Mitfords into his orbit; only her sister Jessica was totally, completely repulsed—in fact, to the point that it probably helped push her leftward, and she ran off with a Communist cousin who’d fought in Spain and had been one of the protestors at Olympia. (She ended up in the United States where she wrote the highly respected The American Way of Death, an exposé of the funeral industry.) Nancy had at one point subscribed to The Blackshirt and been at Olympia alongside Diana. But she’d already begun to turn on her sister with the 1935 publication of Wigs on the Green, a satire of the BUF that got her disinvited from the Mosley home for the next several years. She went to Spain, helping Republican refugees, which helped galvanize her further against the Nazis.
On May 23, 1940, Mosley was arrested under Rule 18B of the Emergency War Powers Act, which gave the government sweeping powers to arrest and hold anyone indefinitely, without a trial. Afterward, it was perhaps a matter of time for Diana. Unity wasn’t imprisoned, because when Britain declared war on Germany, she shot herself in the head, and while she didn’t die, she was never the same after the traumatic brain injury. But the fact that Unity had been so publicly, revoltingly devoted to Hitler probably didn’t help Diana’s cause. Then there was the testimony of her former father-in-law, Lord Moyne, who’d formerly adored her and now had her Guinness son’s governess watching for any signs of Nazi sympathies: “It has been on my conscience for some time,” Laura Thompson quotes his letter to the Chairman of the Defense Security Executive in her book The Six, “to make sure that the authorities concerned are aware of the extremely dangerous character of my former daughter-in-law, now Lady Mosley.”
Nancy didn’t know about the attempts to wrangle a radio license, according to Mary Lovell in her book The Sisters, but she knew that her sister had been traveling to Germany frequently. And she, too, informed: “I advised him to examine her passport to see how often she went. I also said I regard her as an extremely dangerous person. Not very sisterly behavior but in such times I think it one’s duty,” she wrote to a confidant.
There are a number of ways to read the relationships between the various Mitfords and their respective ideologies. Laura Thompson, in The Six, goes into great detail about the miserable conditions in Holloway Prison—where Diana would spend more than three years—and her dignity in the face of awful circumstances. Jessica is portrayed as a bit of a bolshie brat, which seems unfair considering that, again, her family was full of people who fully went Nazi. I personally cannot discuss Diana without screaming “HITLER WAS AT HER WEDDING!” at the top of my lungs. Presumably, Nancy did not regret betraying her sister as the bombs rained down on London, night after night, at the height of the Blitz. It’s that multiplicity of readings that has attracted the fascination of so many over the years—and a testament to the seductiveness of Diana that so many have been willing to make the excuses for her that Nancy didn’t in 1940.
In fact, her relationship with Nancy thawed out over the course of her time behind bars. Nancy eventually began visiting, and once the authorities let Diana’s children make occasional visits, they sometimes stayed overnight with their aunt. After the war, she was released; Mosley tried periodically to revive his political fortunes, but the period where British aristocrats could speculate that perhaps the United Kingdom might make common cause with Hitler was long gone. They settled in France, where Nancy already lived; the two sisters remained close to the end of Nancy’s life. When she got sick, Diana drove from Orsay to Versailles for visits constantly—despite the carping of Mosley, who wanted her to himself. (Shocker.)
Diana didn’t find out Nancy had testified against her until after Nancy died. In 1989, she went on Desert Island Discs, a BBC radio interview program structured around what records the guests would choose to be stranded with. Asked about Hitler, she admitted forthrightly: “I admired him very much.”
Who knows you better than your sister?