It was probably a New Year’s resolution that started her diary, one she thought nobody would see and which would have been lost for ever were it not for the sharp eyes of a volunteer at an Oxfam shop in Bristol.

Ilene Powell was 17 when she began jotting down the details of her life and loves in pencil in a leather-bound book on January 1 1925. Bridget Jones, Helen Fielding’s fictional self-obsessed singleton, did not appear until nearly 70 years later, but the similarity between the two is uncanny.

Ilene’s diary, found in an attic and given to Oxfam with a pile of jumble long after her death, paints a fascinating portrait of life for the first generation of girls to throw off the shackles of centuries and become prototype modern women.

When she was born in 1908 skirts were ankle-length and young women wore their hair long. By the time she began her diary, their skirts were past the knee (and still rising) and hair was “bobbed”. They also had money to spend.

Like Bridget Jones, Ilene was neurotic about her looks and weight and was ardently pursued by a number of “chaps”. She was a shopaholic who loved clothes and make-up and was up for a night out at the slightest excuse. She smoked and drank and, like Bridget, was meticulous about charting her personal details.

The first entry in her diary, written on the inside cover, reads: “Glove size (6) boot size (3) hat size (6 and five-eighths) Weight (8st) and height (5ft 3in).”

Bridget moons over Mark Darcy and Daniel Cleaver. Powell has “the lads” — Bill, Bob, Mervyn, Norman and Claude — who race her around Bristol in their motor cars and accompany her to the theatre and to tea dances. Life revolves around lunch, having tea, playing table-tennis, shopping and dancing the Charleston and the Black Bottom.

Saturday February 7 1925 was a typically exhausting day: “Met Vera as usual and had coffee with the lads in the Oakroom. Went to tea dance with Bill, Mollie, Vera, Clarie and Mervyn. I danced with Jack Gough, Ken Hughes etc. Jack pinched car and took me to the White Ladies. Danced with all the lads as usual. Had a good time, six people asked to take me home. There was a fight and Mrs Morgan fainted. Ticked off JG for making love to me on the roof garden! Home at 1.30 o’c.”

The fun continued on Sunday: “Got up soon after 11 o’c. Mollie, Bill, Jack and Mervyn came to tea. At 6.30 4 other boys called to take Mollie and I to ‘Ship’ (2 boys each!). Enjoyed ourselves, did 59mph in Buick coming home. The boys came in and danced for an hour after 1 o’c. Beat Jack at table-tennis.”

A month later, on Sunday March 18, Ilene writes: “Had a lively time fighting the boys, dashing round the black houses etc after blacking Bill’s face with burnt corks. Bill drove Vera and Mollie home.”

All this jollity took place in the retreating shadow of the great war. The British Empire lost 1m young men in the first world war and part of their legacy was a freedom for Ilene and her friends that no generation of women had enjoyed before. During the war, women had worked in offices and managed munitions factories and after the war they were — understandably — reluctant to return to humdrum lives in the home.

The general shortage of men — not something Ilene seems to have suffered — meant there was a practical need for women to be independent. It was, as Rosalind Miles, author of The Women’s History of the World, points out, “no good acting helpless and waiting for Johnny Handsome to come along. Women had to be able to do things for themselves”.

The horrors of mass slaughter in the trenches reverberated through everyday moral life. The loss of so many young men meant that young and old decided life was now to be lived fast and to the full.