Billie Fleming: Long-distance cyclist who rode nearly 30,000 miles across Britain in a calendar year, a record that stands to this day

She didn't have the benefit of Lycra. No support team accompanied her, and her bike had a mere three gears. Yet despite these disadvantages, on 1 January 1938 an attractive young Englishwoman touted in advertisements as the "Rudge-Whitworth Keep Fit Girl" embarked from the Royal Horticultural Hall in Westminster, and, over the 365 days that followed, cycled into the record books.

In towns and villages and leafy rural byways across the country, unsuspecting members of the public found themselves hailed by a fresh-faced 24-year-old with wavy hair and a long slender neck. Would they be so kind, she asked, and sign her checking card? These documents, marked with witnesses' names and addresses, sighting locations, and cyclometer readings, established that by the end of December, Billie Fleming – or Billie Dovey, as she then was – had completed nearly 30,000 miles: further than any woman had ever cycled in a year.

This achievement was all the more remarkable for the fact that she hadn't particularly set out to achieve it. Moreover, young Billie had only learned to ride a bicycle a few years before.

Born Lilian Irene Bartram, the daughter of a toolmaker, she was educated locally in North London, then at 16 took a job as a typist. Two years later she was initiated into cycling by a boy who took her to the Barnet Bypass, and rode his bike beside her as she wobbled along on hers, to protect her from passing cars. Always a tomboy, "Billie" soon got the hang of it, and by her own account, became "besotted".

She conceived a plan to try to cycle every day for a year. Her goal, she said, was to illustrate the principles of the Women's League of Health and Beauty, whose credo was that instead of sitting around at home, women should get out there and engage in hard physical exercise. Billie took a similar view, and after writing to dozens of companies, she received a reply from the bike manufacturers Rudge-Whitworth, who donated a machine with curving drop handlebars, and a saddlebag into which she packed some clothes and tools in case of repairs.

Her route was haphazard. Sometimes she returned to Mill Hill in London where she lived with her husband, Freddie Dovey. More often than not she rounded the day off by delivering a talk on the joys of fitness in a village hall or an outlet of Rudge-Whitworth before checking into a hotel or B&B and sleeping the sleep of the long-distance cyclist. Most of the time, fortune smiled. The summer of 1938 was gorgeously sunny, she recalled. And when it rained? That was "not funny", she admitted. "But the good days make up for all the bad ones."

Asked to name the highlight among the countryside she'd explored, she said that "everywhere was interesting", but her heart had thrilled to the surging hills around Sutton Bank in North Yorkshire. It was from York that she began her most epic day's cycle – more than double her daily average of 81 miles – when she awoke one morning and decided to cycle home to London: a distance of 196 miles.

As the winter came on and proved to be a bleak one, the test grew tougher for the Rudge-Whitworth Keep Fit Girl. But she kept at her task, never forgetting to post her checking cards at regular intervals to HH "Harry" England, the legendary editor of Cycling magazine (now Cycling Weekly), who was officially charting her progress.

As a result, by the time she hove into view at the Royal Horticultural Hall on 31 December, where a smiling England headed the reception committee, he was able to confirm not only that she had achieved her aim of cycling every day for a year, but also that her total distance was 29,603.4 miles precisely. That's around 50 times the aerial distance between Land's End and John O'Groats, or to put it another way, three times the distance from London to Sydney.

The following year she had plans to cycle across America, but the outbreak of the Second World War made that impossible. She worked in the buying office of an aircraft company, but still found time, in 1940, to break three women's tricycling records, at 25, 50 and 100 miles. After the War her first marriage hit the skids, but Billie got back on the saddle, quite literally, with her second husband, George Fleming, who was also a record-breaking cyclist. The couple took cycling holidays together, once crossing the Pyrenees from the Atlantic to the Mediterranean.

Billie Fleming, who lived to be 100, didn't cycle a great deal in her later decades. It wasn't such fun, she said, now there was so much more traffic on the roads. In the care home in North Devon where she spent her final years she liked to watch the Tour de France on the television. However, she pronounced herself amazed at all the high-tech equipment, not least the modern insistence on bicycles having such an exorbitant number of gears. "You can't tell the difference between them," she declared. "Three is plenty. Thirty-three is ridiculous."

The Rudge-Whitworth Keep Fit Girl's record – of distance cycled by a woman over the course of a year – stands to this day.

Lilian Irene "Billie" Bartram, long-distance cyclist: born 13 April 1914; married firstly Freddy Dovey (marriage dissolved), secondly George Fleming; died 12 May 2014.