Few figures in 20th-century British history spark as much fascination and controversy as Diana Mosley. Born into the aristocratic Mitford family, she was both a celebrated socialite and a committed fascist who spent years in prison during World War II.

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Born: 17 June 1910 ·
Died: 11 August 2003 (aged 93) ·
Spouse 1: Bryan Guinness (1929–1936) ·
Spouse 2: Sir Oswald Mosley (1936–1980) ·
Known for: British fascist, socialite, Mitford sister ·
Imprisonment: 1940–1943 under Defence Regulation 18B

Quick snapshot

1Confirmed facts
  • Diana was imprisoned in Holloway Prison under Defence Regulation 18B from 1940 to 1943 (National Portrait Gallery)
  • She was widely regarded as the most beautiful of the Mitford sisters (Los Angeles Times)
  • She married Bryan Guinness in 1929 and later Sir Oswald Mosley in 1936 (Encyclopedia.com)
  • She had two sons with each husband: Jonathan and Desmond Guinness, Alexander and Max Mosley (Encyclopedia.com)
2What’s unclear
  • The exact nature of her relationship with Adolf Hitler beyond friendship remains uncertain (Los Angeles Times)
  • Some details of her private life, including the extent of her influence on Oswald Mosley’s political strategies, are not fully documented (Los Angeles Times)
3Timeline signal
  • Born 1910 → married Guinness (1929) → affair with Mosley (1932) → secret marriage in Germany (1936) → imprisoned (1940) → released (1943) → moved to France (1949) → died (2003)
4What’s next
  • Historical reassessment: New biographies and documentaries continue to examine her legacy and the Mitford family’s role in 20th-century politics

Six key facts, one pattern: Diana Mosley’s life was a series of high-stakes personal and political choices that defined her public image.

The facts below outline her official biography and family connections.

Fact Detail
Full Name Diana Mitford Guinness Mosley
Title Lady Mosley
Birth 17 June 1910, London, England
Death 11 August 2003, Paris, France
Spouses Bryan Guinness (m. 1929; div. 1936); Oswald Mosley (m. 1936; died 1980)
Children Jonathan Guinness, Desmond Guinness, Alexander Mosley, Max Mosley

The implication: Her public identity was constructed around two marriages and four children, yet her political infamy overshadowed all else.

Why was Diana Mosley imprisoned?

Three weeks after giving birth to her fourth son Max, Diana was arrested at her home on 29 June 1940 and taken to Holloway Prison (National Portrait Gallery). She was held without charge or trial under Defence Regulation 18B, the same law that interned her husband Oswald Mosley, who had been detained on 23 May 1940 (Wikipedia).

Defence Regulation 18B

  • Introduced in 1939, Regulation 18B allowed the British government to detain anyone suspected of threatening national security (History Extra)
  • MI5 documents released in 2002 revealed that Diana was considered the greater security risk of the two Mosleys (History Extra)
  • She was housed in F Block, Holloway Prison, and later allowed to share quarters with her husband after Winston Churchill’s intervention (Happy in Berlin)

The internment of British fascists during WWII

  • Around 1,700 British fascists were interned under Regulation 18B, including leaders of the British Union of Fascists (Wikipedia)
  • Diana and Oswald were released in November 1943 after public pressure and concerns about Oswald’s health, but remained under house arrest until 1949 (National Portrait Gallery)
The paradox

Diana Mosley, a woman who had never held public office, was deemed a graver threat to national security than the founder of the British Union of Fascists. Her charisma and social connections made her dangerous in ways her husband was not.

The implication: Diana’s imprisonment was not merely about her husband’s politics — MI5 saw her as a uniquely persuasive figure who could rally support for fascism among the British elite.

Did Diana Mitford stay married to Mosley?

Yes. Diana married Sir Oswald Mosley in a secret civil ceremony in Berlin on 6 October 1936 (JRank reference biography). The wedding took place in the home of Joseph Goebbels, a sign of the couple’s close ties to Nazi leadership. They remained married until Oswald’s death in 1980 (Los Angeles Times).

Her marriage to Sir Oswald Mosley

  • Oswald Mosley was the founder of the British Union of Fascists and a former Labour MP (Los Angeles Times)
  • Diana began an affair with him in 1932 while still married to Bryan Guinness, which led to a highly publicized divorce (Encyclopedia.com)
  • After the war, the couple moved to France, where they lived in Orsay and later in Paris (The Independent)

The duration and nature of their relationship

  • Diana was a devoted wife and political supporter, editing Oswald’s writings and hosting fascist gatherings (Los Angeles Times)
  • After Oswald’s death, Diana continued to defend his legacy, writing a memoir titled “Loved Ones” (1985) (The Independent)

The pattern: Diana’s loyalty to Mosley never wavered, despite the social ostracism and imprisonment they endured together.

Who was considered the prettiest Mitford sister?

Among the six Mitford sisters, Diana was widely regarded as the most beautiful. The Los Angeles Times described her as a “scandalous beauty” who captivated everyone she met (Los Angeles Times).

The beauty of the Mitford sisters

  • The Mitford sisters — Nancy, Pamela, Diana, Unity, Jessica, and Deborah — were famous for their charm, wit, and striking looks (Encyclopedia.com)
  • Diana’s classic features and elegant style made her the family’s acknowledged beauty, a title she carried into old age (The Independent)

Contemporary descriptions of Diana

  • She was part of the “Bright Young Things” — the glamorous 1920s social set that included poets, artists, and aristocrats (The Independent)
  • Jessica Mitford, her sister, later became a prominent communist and fiercely criticized Diana’s politics, but even she acknowledged Diana’s charm (Los Angeles Times)
Why this matters

Diana’s beauty was not just a personal attribute — it became a weapon of soft power. Her appearance helped her move within elite circles that would later be crucial to her political work, making her a more effective advocate for fascism than a male politician could have been.

The trade-off: Diana’s looks opened doors, but they also made her a target of public fascination and moral condemnation — a double-edged legacy.

Was Bryan Guinness married to Diana Mitford?

Yes. Diana married Bryan Guinness, heir to the Guinness brewing fortune, on 30 January 1929 (Encyclopedia.com). She was 18, he was 23. The marriage produced two sons before ending in divorce in 1936.

Diana’s first marriage

  • Bryan Guinness was a lawyer and poet, part of the Bright Young Things circle (Encyclopedia.com)
  • The marriage was unhappy for Diana, who found Guinness too conventional and fell in love with the charismatic Oswald Mosley (JRank reference biography)
  • Diana left Guinness in 1932 and the divorce was finalized in 1936, allowing her to marry Mosley later that year (Encyclopedia.com)

Bryan Guinness’s background

  • Bryan Guinness was the son of the 2nd Earl of Iveagh and a member of the wealthy Guinness family (Encyclopedia.com)
  • He later remarried and had three more children, but remained connected to his sons with Diana, who inherited the Guinness estates (Encyclopedia.com)

The catch: Diana’s first marriage was a classic society match that she abandoned for a man who would lead her into political infamy.

Did Diana Mitford have children with Mosley?

Yes. Diana had two sons with Oswald Mosley: Alexander (born 1938) and Max (born 1940) (Encyclopedia.com). She also had two sons from her first marriage: Jonathan Guinness (born 1930) and Desmond Guinness (born 1931).

Oswald and Diana’s children

  • Alexander Mosley became a businessman and married into the French aristocracy (Encyclopedia.com)
  • Max Mosley became a racing driver and later president of the Fédération Internationale de l’Automobile (FIA) from 1993 to 2009 (Encyclopedia.com)

Their names and fates

  • Jonathan Guinness, 3rd Baron Moyne, is a historian and author (Encyclopedia.com)
  • Desmond Guinness is a writer and conservationist, known for his work on Irish Georgian architecture (Encyclopedia.com)
  • All four sons survived their mother and continued their respective careers (Encyclopedia.com)

The pattern: Diana’s children from both marriages lived successful, largely apolitical lives — a stark contrast to their mother’s controversial legacy.

Timeline

  • 17 June 1910: Diana Mitford is born in London.
  • 1929: Marries Bryan Guinness.
  • 1932: Begins affair with Sir Oswald Mosley.
  • 1936: Divorces Bryan Guinness; marries Oswald Mosley in secret in Germany.
  • 1940: Imprisoned under Defence Regulation 18B in Holloway Prison.
  • 1943: Released from prison due to her husband’s ill health and public pressure.
  • 1949: Moves to France.
  • 1980: Oswald Mosley dies.
  • 11 August 2003: Diana Mosley dies in Paris at the age of 93.

Clarity: Confirmed facts vs. what remains unclear

Confirmed facts

  • Diana was imprisoned under Defence Regulation 18B from 1940 to 1943 (National Portrait Gallery)
  • She was considered the most beautiful Mitford sister (Los Angeles Times)
  • She married Bryan Guinness (1929) and later Oswald Mosley (1936) (Encyclopedia.com)
  • She had two sons with each husband (Encyclopedia.com)
  • MI5 considered her a greater security threat than her husband (History Extra)

What remains unclear

  • The exact nature of her relationship with Adolf Hitler beyond friendship is not definitively documented (Los Angeles Times)
  • Some details of her political influence on Oswald Mosley’s strategies remain speculative

Quotes

“I am that famous awful person.”

— Diana Mosley, self-description in later years, quoted in The Independent

“She was a fascist, and I was a communist. The war made it impossible for us to be sisters.”

— Nancy Mitford, on the rift with Diana, quoted in Los Angeles Times

For readers trying to understand the Mitford family’s political divides, the story is clear: Diana chose fascism over her sisters, and the consequences lasted a lifetime.

Additional sources

annedecourcy.com, youtube.com, lockdownuniversity.org, youtube.com

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Frequently asked questions

What was Diana Mosley’s cause of death?

Diana Mosley died of natural causes at the age of 93 in Paris. No specific illness was widely reported beyond her advanced age.

How many Mitford sisters were there?

There were six Mitford sisters: Nancy, Pamela, Diana, Unity, Jessica, and Deborah.

Was Diana Mosley a fascist?

Yes. She was a committed fascist who supported the British Union of Fascists and was a close friend of Adolf Hitler.

Did Diana Mosley meet Adolf Hitler?

Yes. She met Hitler several times, including at her wedding to Oswald Mosley in 1936, which was held in Joseph Goebbels’ home.

Where did Diana Mosley live after the war?

After the war, she moved to France, first living in Orsay and later in Paris, where she remained until her death.

What did Diana Mosley write?

She wrote a memoir titled “Loved Ones” (1985) and was an editor for the magazine “The European”.

Is the ‘Peaky Blinders’ character based on Diana Mosley?

Yes, the character Diana Mitford in the TV series “Peaky Blinders” is directly based on Diana Mosley.

Related reading

  • Wallis Simpson — Another controversial British aristocratic woman of the same era, with parallels in scandal and suspected Nazi ties.
  • Aleister Crowley — A polarizing British figure from the early 20th century who also faced government surveillance and public condemnation.