Books: What the Queen Mother does in the bath

Girlitude: A Portrait of the 50s and 60s by Emma Tennant Cape pounds 15.99

In Strangers, published last year, Emma Tennant exorcised a long-nurtured obsession with her family history by writing about some of her more colourful and eccentric forebears in a book that was part imaginative reconstruction, part autobiography. Her accounts of Margot Asquith, the spindly waspish-tongued great-aunt who married a prime minister, and of uncle Stephen, the beautiful aesthete who became fat and raddled and "radiant with self-love", possessed an immediacy that seemed to take us beyond all those family portraits by Sargent and Beaton. And in the glimpses of her own childhood at the family seat at Glen, a fake baronial castle in Scotland built from the Tennant chemicals fortune, Emma Tennant portrayed an isolated upbringing in which she suggested that the clues to her own future were somehow buried in her family's past.

Girlitude takes up Emma Tennant's own story in the early 1950s, and follows it through to the end of the 1960s. Where Strangers had a sedate, almost dreamy quality, its sequel is more of a headlong rush through myriad events and disparate personalities. Tennant's own disorientation and lack of self-direction are reflected in the disjointed, breathless narrative which relates the tale of a reluctant debutante who, by the end of this volume, is enjoying a flirtation with radical chic in Paris during "les evenements" of 1968.

In its opening pages, Tennant surveys herself as a girl of 17 in 1955 at the opening of her first season: dressed in silk tartan, and looking much older than her years, she is photographed by the young Antony Armstrong- Jones shortly before her coming-out ball at her father, Lord Glenconner's house overlooking Regent's Park. A pillar of dry ice has been ordered specially for the occasion to lend an exotic touch, a bank of temporary lavatories has been plumbed in in the basement, and to top it all, Princess Margaret Rose, the Queen's sister, is to grace the occasion. Princess Margaret, we are told, has brought unwelcome publicity to the Tennant family because of her friendship with Emma's elder half-brother, Colin (later of Mustique), but the expected engagement is never announced and, disappointingly, Emma Tennant has no dirt to dish on the Princess.

For upper-class girls of the period with background, breeding, but no inheritance (in Tennant's case it was all entailed on the older brother), and little education, the only escape from "girlitude" was into the arms of the first reasonably rich, unmarried young man who strayed across their paths. Emma Tennant tried marriage - disastrously - three times, and the strength of this memoir lies in the ways in which it convinces us that the mistakes she made as a young woman were as a result of her need to establish an identity, and in doing so, to find some self-respect.

The problem is that none of the identities she assumes seems quite to fit. As a wife she displays an alarming penchant for falling for prospective fathers-in-law and then marrying their sons (this happens twice, first when she marries Matthew Yorke, son of her literary idol, the novelist Henry Green, and again when she marries Alexander Cockburn (though she appears more entranced by his father, the journalist Claud Cockburn). As a writer, trading under the name Catherine Aydy, she publishes her first novel, The Colour of Rain, in 1963, only to find herself ostracised by the husbands and wives of the smart set whom she had gently satirised in its pages. The book, which is said to bear stylistic debts to Henry Green, was submitted for the Formentor Prize but was denounced by one of the judges, Alberto Moravia, as "a symbol of the decadence of English writing today". His comment was enough to silence Tennant as a writer, and she didn't publish another book for nine years.

Even as a Tennant she is riven by internal family feuds and by a sense that in the aristocratic hierarchy the Tennants, with their fantastical Disney-style castle and their fortune from the sale of bleach, are too nouveau riche to count for much. "The trouble with you," a friend tells Emma Tennant, "is that you're an orgiast. You want too much all at the same time." And so she does. As she herself admits, "I can be Bohemian, literary, and still thirty-odd floors up in the most expensive building in New York."

In the midst of all these shifting identities are one or two pen-portraits which stick in the mind. For those who can never have enough Bruce Chatwin, there is an engaging picture of him on one of his scavenging missions, descending a stairway carrying a marble statue of a youth, partly obscured by the buttocks; and the best single anecdote is that of Lord Leicester who in his later years was given "to the unwelcome habit of telephoning the Queen Mother and announcing he knew her to be in the bath, soaping her breasts".

"Girlitude", Tennant tells us, is a term of self-reproach for a species. Her memoir has self-reproach aplenty, and also honesty, wit, and a powerful economy of style. A third volume should cover the period when Emma Tennant finally takes flight as a writer, discovers science fiction, and founds the literary magazine Bananas. I feel that I can hardly wait.