Athletics: 50 years ago, Roger Bannister became a sporting legend with his four-minute mile. Why is his female equivalent just seen as an also-ran?

Fifty years ago next month, on an English cinder running-track, a British athlete ran a mile faster than many believed possible. Not only was the time the fastest ever recorded, but it broke a barrier that had hitherto appeared unbreakable - five minutes. But because the athlete was a woman, her world-best performance did not count as an official record.

Just 23 days previously, on a cinder running-track some 70 miles away, another British athlete had also run a mile faster than anyone thought possible. Again, a previously unattainable barrier was broken - this time of four minutes. That athlete, Roger Bannister, became a household name, and his achievement was recognised by a knighthood. The anniversary of his world record on 6 May is being marked by several high-profile sporting events around Britain, the publication of four books, and a BBC2 documentary. Yet few even remember the name of the woman miler.

There was a modest crowd at the Midlands Women's AAA Championships at Birmingham's Alexander Stadium on 29 May, 1954. Photographs of the day show women in headscarves and men in flat caps standing beside the railings and watching the local runners. No doubt many of them were congratulating themselves for having turned up, as there had already been some gripping action. A tall, striking 21-year-old athlete called Diane Leather, whose looks reminded many of Audrey Hepburn, had set a British all-comers best in the 880 yards. Leather, who had only started running two years previously - after being inspired to take up the sport by watching the Helsinki Olympics on television - was already known to most of them. Just three days earlier, to the delight of the local press, the surgeon's daughter had set an unofficial world record for the mile of 5min 0.2sec, breaking the previous world-best performance of 5min 2.6sec - itself a record that she herself had set just eight months before. The records were deemed unofficial as, unlike the men's distance, the International Amateur Athletic Federation did not recognise the women's mile in international competition.

Despite a rain-sodden track, an 8mph crosswind, and having set a new British record less than an hour ago, Leather was determined to break the five-minute mile. The athlete, who lived with her parents in Streetly, near Birmingham, and worked as a microanalyst at Birmingham University, told reporters: "I feel fine, I'm going to have a go at the mile for a double."

Unlike Bannister's attempt, there were no pacesetters. At the three-quarter mile timekeeper's announcement, the crowd began to suspect that No 88, in the puffy black shorts and matching T-shirt, which bore the words "Fleet and Free" (the motto of her club, Birchfield Harriers), could break the five-minute barrier. Around 100 yards ahead of her nearest competitor in the last straight, she triumphantly crossed the line in 4min 59.6sec. In characteristic understatement, on learning of her achievement she said to waiting reporters: "Oh good, at last." When Bannister had crossed his line, he was whisked away in a waiting car to appear on BBC evening television. Leather went for a quiet drink with her coach and club secretary, both women.

Sitting at her kitchen table in her Cornish farmhouse just outside Truro, Diane Charles (as she is now, she married Peter in 1959) is still the unassuming woman that the press described 50 years ago. It soon becomes clear that she is not one to wallow in her achievement. Her husband, by contrast, is tickled pink that someone has remembered his wife's achievement, and has spent large parts of the day rooting around the loft looking for her medals and trophies, then studiously polishing them. Diane has banned him from the kitchen as, she says, she knows he will try to "blow my trumpet". At one stage, he sits on a chair behind the door muttering "blood out of a stone", and then breaches the ban by depositing on the table the pair of shoes his wife was wearing when she broke the five-minute mile, which he had silver-plated.

Her hair is still cut into a gamine crop, but now, at 71, it is almost white, and Diane has lost half an inch off her once-5ft 10in frame. She walks with a slight limp, which she says could be down to the running, but she doesn't really notice it. In front of her, no doubt dusted down by her husband, are several albums filled with newspaper cuttings, stuck to the pages with sticky tape that has turned butterscotch with age.

"I think I did wake up nervous that day," she remembers. "You always did. The mile was important to me because it had gone down, year after year, to five minutes. Then everyone was saying that someone was going to break it, and it happened to be me. I suppose I knew that I could do it by then because I had got near it the September before, with 5 2.6, and then I missed it by a stride at 5 0.2 on 26 May. It was great to win the 880. I suppose that gave me a buzz ready for the mile, and being fit, obviously, running two races was OK." Her tone is surprisingly matter-of-fact.

"I was thrilled to bits to have broken it. It was very exciting. There was lots of publicity and I was invited to tea with the Lord Mayor of Birmingham. It was on the Pathé news. Some people in the papers called it a world record, and it's the same thing in effect, but because it wasn't a recognised international event [for women], they called it a 'world-best performance'."

Did that distinction upset her at the time?

"No, no, no, you know it's the world best, it doesn't matter..."

Despite her momentous achievement, Stan Greenberg, editor of Whitaker's Olympic Almanack and former BBC and Amateur Athletic Association statistician, believes that her and Bannister's performances were incomparable. "Though it was a landmark, hers wasn't such a fantastic performance by any means," he says. "That may be why people don't remember it as such. It bears no comparison really to the four-minute men's mile because people had been trying to do that for 50, 60 years. Longer, in fact. It had no significance. If you were the world's greatest miler, for instance, so what? You never had a chance to prove it in any championships, or, indeed, on a world-record level."

The history of this discrimination is remarkable. "At one time, many countries didn't allow women to run. They thought they would kill themselves and it would interfere with childbearing, so they didn't start properly until the Twenties, whereas men had been running since, certainly in terms of recorded stuff, the late 19th century."

But some, such as Norma Blaine, who competed with Diane in national events, and became Birchfield Harriers' first woman chairman, are appalled at the difference in which the two achievements are regarded. "It upsets me very, very, much when the men's four-minute mile is always mentioned, but the first lady to have done the five-minute mile is never recorded as such. I do feel that Diane lost out a lot on that issue. I remind people of Diane's achievement when I'm on a committee meeting, if they talk about the men's four-minute mile. She was brilliant, absolutely brilliant. She'll probably say that she was nothing, but she was a superior athlete throughout the whole of her running career. She was always breaking a record. She won the national cross-country title I don't know how many times. She was not an aloof international athlete, she was a Birchfield Harrier and a team member. She was quiet and unassuming and wouldn't brag about what she had done. I do feel that she has been forgotten."

Not being accredited with official records was something that Diane Charles had to get used to throughout her career. She improved on her mile twice the following year, getting it down to 4min 45sec. Again, those performances, as well her time of 4min 30sec in the 1500m in Hornchurch in 1957, were labelled "world best". The distances didn't become an International Amateur Athletic Federation category for women until the late 1960s.

"The world athletic authorities in those days didn't recognise women running anything more than 200m," she explains. "The year 1928 was the last time they had the 800m in the Olympics, and it wasn't reinstated until 1960. They thought it was too much for women, or something. In the 1956 Olympics, in which I was good enough to compete, they still didn't have anything over 200m. It was disappointing that you were a runner, and there wasn't an event."

Women were also excluded from running the 800m in the Commonwealth Games. Diane was, however, able to run the distance in the European Games, and came second in both 1954 and 1958. By the time they re-introduced the event in the 1960 Olympics in Rome (at which she was appointed vice-captain of the British team), Diane was past her best and failed to get into the final. "It was disappointing," she admits.

Despite the restrictions, Diane produced a staggering record of achievements, and one of which she isn't aware until she counts them up in front of me from her page in a Birchfield Harriers record book. In just four years, she achieved three world records (the 3x880yds in 1953 and the 880yds and the 3x880yds in 1954); six "world best" performances (five goes at the mile and the 1500m); and numerous British records.

"She was a far better runner over 800m. She was one of my favourite runners," Greenberg admits. "She was very tall and long-legged, and had what they call a ground-devouring stride... She had some tremendous races against Russians and Eastern Europeans in international matches. She was a very well-established international star over 800m."

Diane Charles's life took a very different course after she retired from competing in 1960. Amazingly, she never ran again - not even a jog for the pleasure of it. There was simply no time. The first of her four children was born in 1961, she became a Samaritan and fostered half-a-dozen babies. In 1973, she went into social work in London, and then, when the family moved to Cornwall in 1986, she specialised in child protection until her retirement in 1998. "It was quite tough," she says. "You're in court, looking at children who've been abused and taking children away, which isn't pleasant. But I found it very rewarding." Diane is still busy as vice-chair of the Cornwall branch of Cruse Bereavement Care, and volunteer for a child bereavement charity and a hospice.

She acknowledges, however, that breaking the five-minute mile was her biggest achievement. She says that she doesn't feel it has been forgotten, and offers, by way of example, the fact that she was chosen by Birmingham as one of their "100 Great Brummies" in 1990. "People of an age would remember it. The younger people don't even know about it. That's life, isn't it? Occasionally, people will say, 'I heard your name on the radio quiz the other day'."

She still gets invited to special events by Birchfield Harriers, who are based at the stadium where she broke the mile. Inside the clubhouse, her photo hangs with those of other past champions. The club, however, is not marking the anniversary of her record. Brian Abbey, a life vice-president, says that it didn't occur to them. Norma Blaine, however, believes that had a world record been achieved by a man, it would almost certainly have been marked.

Will Diane Charles be doing anything to mark her own anniversary? "I don't think so," she replies. Instead, she will be helping Roger Bannister to celebrate his anniversary. It is being marked by a commemorative match modelled on his feat at Oxford University, with many of the greatest milers in attendance. The university has approved £40,000 from its funds to stage the event, which will see an Amateur Athletic Association of England team take on an Oxford University team past and present.

Diane has also been invited to a formal dinner afterwards, hosted by Bannister. The pair have met at a couple of functions over the years. "She's a very nice person and I look forward to seeing her on 6 May," says Bannister. "It was a minority activity, but obviously she was better than anyone else around, and therefore it stands to her credit as a world record. All credit to her. She's not forgotten by me."