Born as Rotha Beryl Lintorn Orman in Kensington, London, she was the daughter of Charles Edward Orman, a major from the Essex Regiment, and his wife, Blanch Lintorn, née Simmons. Her maternal grandfather was Field Marshal Sir Lintorn Simmons. The Orman family would adopt the surname of Lintorn-Orman in 1912.
Rotha Orman, with her friend Nesta Maude, was among the few girls who showed up at the 1909 Crystal Palace Scout Rally wanting to be Scouts which led to the foundation of the Girl Guides. In 1908 they had registered as a Scout troop, using their initials rather than forenames. In 1911 she was awarded one of the first of the Girl Guides' Silver Fish Awards.
In the First World War, Lintorn-Orman served as a member of the Women's Volunteer Reserve and with the Scottish Women's Hospital Corps. She was decorated for her contribution at the Great Thessaloniki Fire of 1917 but invalided home with malaria. In 1918 she became head of the British Red Cross Motor School to train drivers in the battlefield. In these early years she developed a strong sense of British nationalism, and became a staunch monarchist and imperialist.
Following Lintorn-Orman's war service, she placed an advertisement in the right-wing journal The Patriot seeking anti-communists. This led to the foundation of the British Fascisti (later the British Fascists) in 1923 as a response to the growing strength of the Labour Party, a source of great anxiety for the virulently anti-Communist Lintorn-Orman. She felt Labour was too prone to advocating class conflict and internationalism, two of her pet hates. Nicholas Mosley would claim that she got the idea to save Britain from communism one day while she was weeding her kitchen garden.
Financed by her mother Blanch, Lintorn-Orman's party nonetheless struggled due to her preference for remaining within the law and her continuing ties to the fringes of the Conservative Party. Lintorn-Orman was essentially a Tory by inclination but was driven by a strong anti-communism and attached herself to fascism largely because of her admiration for Benito Mussolini and what she saw as his action-based style of politics. The party was subject to a number of schisms, such as when the moderates led by R. B. D. Blakeney defected to the Organisation for the Maintenance of Supplies during the 1926 General Strike or when the more radical members resigned to form the National Fascisti, and ultimately lost members to the Imperial Fascist League and the British Union of Fascists when these groups emerged. For her part Lintorn-Orman would have nothing to do with the BUF as she considered Oswald Mosley to be a near-communist and was particularly appalled by his former membership of the Labour Party, although it was to this group that she lost much of her membership when Neil Francis Hawkins became a member in 1932.
Dependent on alcohol and other drugs, rumours about her private life began to damage her reputation, until her mother stopped her funding amid lurid tales of alcohol, other drugs and orgies. Taken ill in 1933, she was sidelined from the British Fascists, with effective control passing to Mrs D. G. Harnett, who sought to breathe new life into the group by seeking to ally it with Ulster loyalism.
She died on 10 March 1935 at Santa Brígida, Las Palmas, Canary Islands, with her organisation all but defunct.
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