The slaughter of a generation of young men in the first world war left a generation of young women without their normal chance of marriage and motherhood. Their fate was already apparent before the war ended. In 1917, the senior mistress of Bournemouth High School for Girls stood up before the assembled sixth form and broke the news: “I have come to tell you a terrible fact. Only one out of 10 of you girls can ever hope to marry.” Her estimate, a former pupil later recorded, proved exactly right. What this generation of women made of their diminished lives, and how the rest of the population regarded them, are the questions that Virginia Nicholson’s pioneering book confronts.

The answer to the second question is – with astonishing spite, resentment and lack of sympathy. When the 1921 census revealed that women outnumbered men by almost 2m, it unleashed a frenzy of vituperation. “The superfluous women,” proclaimed the Daily Mail, “are a disaster to the human race.” They were labelled “limpets” and “bread-snatchers” for taking jobs from demobbed soldiers. They were reviled for forming “unwholesome female friendships” and mocked for lavishing their stifled affection on cats and lapdogs. Sexual psychologists pronounced them unnatural, and Oswald Mosley found them “distressing”. A popular solution was that they should be exported to the colonies. Canada, it was pointed out, had an excess of male trappers and lumberjacks, and even Australia offered many “simple pleasures”.

When, desperate to fill the gap in their lives, they wrote for advice to women’s magazines, they met with heartless optimism (“Cheer up, dears”) or insulting tips on man-catching (“If you use a henna shampoo, don’t overdo it”). Self-help books, with titles such as Sex Philosophy for the Bachelor Girl and Live Alone and Like It, prattled on about taking up folk dancing, astrology or amateur dramatics. But for women whose men had died, the need was to find some way of appeasing their desire for love and their guilt at surviving. An advertisement in the Matrimonial Times read “Lady, fiancé killed, will gladly marry officer totally blinded or otherwise incapacitated by the war.”

Nicholson’s book centres, however, on women who refused to be overwhelmed by grief and struck out in new directions. One of her heroines is Gertrude Caton-Thompson, the distinguished archeologist. The love of her life, a hussar officer, had been killed, and, like many of the bereaved, she felt at first that it was a treachery to him even to breathe and eat. But after the war she enrolled for classes at University College London, learnt Arabic and studied African prehistory. She braved leopards, fleas, fevers, swamps and crocodiles to excavate Neolithic sites in Malta, South Africa, Arabia and Egypt – where she camped out in a tomb with a family of cobras. Other “superfluous women” whose stories Nicholson tells achieved eminence as explorers, entomologists, marine engineers, doctors, mountaineers and fashion models. Some devoted themselves to slum improvement or famine relief, or broke into what had been male preserves – as the first woman solicitor, the first woman director of a firm of stockbrokers, the first woman privy councillor and cabinet member, the first women vets, civil servants and architects. Meanwhile, women novelists shattered the old spinster stereotypes. Muriel Spark’s Miss Jean Brodie transformed the schoolmarm into a sexy elitist; Sylvia Townsend Warner’s Lolly Willowes blossomed into a happy practising witch.

Most of these enterprising single women, Nicholson acknowledges, were from affluent middle-class families. But there were exceptions. Florence White, a Bradford mill-hand, became a leading political activist and the founder of the National Spinsters Pension Association. Gladys Aylward, a London parlour maid, saved up her wages and travelled on the Trans-Siberian railway to China, where, for 20 years, she worked as a missionary, tending lepers and caring for sick children. Less outstanding, but as heroic in their way, were the women who remained satisfied with little. By 1921, there were half a million female clerks (typists, lowly civil servants, secretaries) who lived in bedsits and spent their days clattering away at Remingtons. They earned 30 shillings a week, and lunched off a penny bun or a Marmite sandwich. Social historians have tended to pity them, but Nicholson, interviewing survivors, found them upbeat. They were all girls together and stayed friends for life. They enjoyed dancing at the Locarno or the Palais, walking in Kensington Gardens, and consuming wonderful bacon-and-eggs teas at Lyons Corner House. It was a brave new world – much better than slaving for a husband.

Other single women, with no particular talents beyond the ability to make children happy, found fulfilment as nannies, wheeling perambulators in London’s parks. Often the bonds they formed were closer than those the children formed with their parents, and lasted a lifetime. In 1921, a maiden aunt called Gertie Maclean, much in demand for taking nephews and nieces back and forth to school, decided to make aunthood professional and set up Universal Aunts in the back room of a bootmaker’s in Sloane Street. Soon her “Ladies of Irreproachable Background” were escorting children around London, organising trips abroad and doing other people’s shopping for everything “from a hairpin to a Moth aeroplane”.

Gertie, like the trailblazers in male professions, freed single women from dependence and contempt. Another liberator was Radclyffe Hall, the author of the lesbian novel The Well of Loneliness. Many single women had found happiness with members of their own sex, but the subject was deemed unmentionable until Hall came along.

Even Marie Stopes, renowned as a birth-control campaigner, proved hostile. The letters of women who wrote to her about their sexual feelings provide an extraordinary archive of ignorance, fear and unhappiness. Asked about lesbianism, Stopes replied firmly that it was a “disease”. Hall, by contrast, made it fashionable. When The Well was prosecuted as an obscene libel she appeared in court in a Spanish riding hat and long leather coat, and though her novel was condemned to be burnt, it became a clandestine bestseller. The centre of a galaxy of artistic and theatrical types, including Tallulah Bankhead and the cellist Gwen Farrar, Hall made it her mission that lesbians should never again be “driven back to their holes and corners”.

The women Nicholson celebrates changed our culture. They turned the Victorian spinster into the modern career woman. But, she believes, they were also different from modern women. Like anyone who has lived through a war, they had lower expectations of happiness and a stoicism and dignity that were all their own. Her book applauds the celebrities but does not forget the obscure. Beside Caton-Thompson she sets May Jones, who wrote her autobiography, in Biro, on scraps of coloured paper, when she was 85. She was a Welsh carpenter’s daughter and fell in love with Philip, a young Quaker intellectual, who went to France with an ambulance unit and was killed. “I knew then,” May wrote, “that I should die an old maid.” Then she added, in pencil, “I was only 20 years old.” The rest of the page is blank. It is moments such as this that make Singled Out so powerful and so inspiring.

SINGLED OUT: How Two Million Women Survived Without Men after the First World War by Virginia Nicholson Viking £20 pp326
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