The gloves are on: Meet the British women adding punch to the Olympics' newest sport

The rat-a-tat-tat of five pairs of fists pummelling punchbags echoes around a hall in Sheffield's English Institute of Sport. The sound is interrupted only by the clicking of three skipping ropes, as the country's future Olympic boxing stars begin a day of intensive training.

A near-identical scene has taken place before every Olympic Games for decades, as the chosen few to represent Great Britain go through the necessary and gruelling fitness preparation. But today there is one big difference: while three burly boys are jumping the skipping ropes, the fists making the racket belong to women.

London 2012 marks a watershed moment in boxing: it is the first Olympics at which women will be allowed into the ring. Five women have made the Team GB squad, and for the past two years have been in intensive training in the hope that they can take home one of the coveted first medals.

Just 15 years ago the idea of women competing for any international boxing prize – let alone an Olympic one – would have been unthinkable. It was the final sport deemed simply too rough to let girls play. Which means that to get to this point, most of these five women have had to fight long battles with the authorities just to be allowed into the ring. And after all this hard work, they still may not get to compete in the games: a maximum of three – one from each weight category – can be sent to London.

Nicola Adams is the most delicate-looking of the bunch. She is also Britain's greatest chance of a boxing gold from either sex. She won gold at the European Championships last year and silver at the World Championships in 2008 and 2010. Hopes were raised even further last month when she beat the world number one and current world champion, the Chinese fighter Ren Cancan at the Strandja Cup in Sofia, Bulgaria.

In the lowest weight category, a flyweight at 50kg, she is slim, with the slender hands and wrists of a ballerina. Nicknamed "Babyface", she is 29, but looks little older than 18. Yet the ready smile and slight physique don't hold her back in the ring – she has twice knocked out an opponent and once broke her own knuckle punching a rival.

Recalling the fracture, she gives a wry grin. "What can I say? I punch really hard." More remarkable than the broken digit is that she carried on fighting with it. "I did it in my first competition in the European Championships in 2007. I boxed five times on it and won a silver medal."

Despite possessing a fighter's mentality, she admits to having to repress an instinct to help those she beats. "Every time I've knocked someone out I have this moment where I want to go and say, 'Are you all right?' But you're not allowed to help them up."

Yet her Olympic hopes were nearly dashed three years ago, when she tripped over her own boxing bandage and fell down a flight of stairs. She damaged the vertebrae in her back and was in bed for three months. But, not one to be kept down, the following year, after just a few months' training, she beat a two-time world champion. "I'm afraid of no one. You can't go in the ring with fear. They've got two arms and two legs, same as me."

Adams first boxed when she was 12. "My dad's a big fan of boxing and would always watch the big fights. I used to jump up and punch the air when they were on. I remember we were watching a re-run of the Rumble in the Jungle [the 1974 fight between Muhammad Ali and George Foreman] and I kept jumping up and was told to sit down."

Before turning professional she was studying and working as an extra in television, but now she is focused on the ring. "When you lose, you feel you're letting everyone down. I'm hoping to get gold; I'm going to give it everything."

Because there are no girls of a similar standard at her weight in Britain, Adams has to spar with the boys for practice. One of her sparring partners is 23-year-old Andrew Selby, a flyweight currently ranked number two in the world. He admits that Adams has landed quite a few punches on him and was taken aback by his first encounters with women in the ring. "My gym didn't allow girls. It was probably here that I first came across girls boxing. I think they should be allowed to do whatever they want. People used to say it was a men's sport; some men don't like to see women fight. But if they want to go in the ring and fight, they can."

When Amanda Coulson first donned a pair of boxing gloves in 1998, competing in any international contest seemed almost unthinkable. The ban on amateur boxing for women had been lifted only months before and the first World Championships weren't held until 2001.

The 29-year-old, who is the oldest of the elite squad, was 14 when she saw an article in the paper about two schoolgirls who were about to be the first to fight. The amateur boxing contest in Leicester between a 13- and 14-year-old caused outcry in the media, but it inspired Coulson. "There was a lot of controversy but I thought I'd like to try it. I'd always been a tomboy and I loved sport."

She got out the phone book and started dialling. She rang every club within a 10-mile radius, getting knock-back after knock-back. "They kept saying, 'Girls don't box' or 'We don't have any female changing-rooms' or 'We've got no coaches for girls.' The more people said no, the more I wanted to do it. Finally someone said they'd be happy. It was the Catholic Boxing Club in Hartlepool."

But even then it was a battle to be accepted. "They weren't ecstatic. They didn't want a girl in the gym and a lot of the coaches wanted nothing to do with me. It was a men's gym and many of them went there to get away from their wives and kids. I was eager and keen and, before I knew it, they started to respect me."

She knew she had finally been accepted after winning her first fight. "The club was originally called the Hartlepool Catholic Boys' Boxing Club, but after I won the fight they dropped the 'Boys' bit from the name. Then, I knew I'd won my second bout." Now she is one of the club's longest-serving members and an assistant coach – whenever her punishing Olympic training allows, that is.

Since Coulson began, there has been an explosion in women's boxing across the UK. More than 27,000 women now box at least once a month and at the serious competing end, there are now 1,849 members of the female amateur boxing club in England – up from just 70 in 2005.

Yet the sport is still in its infancy. Female boxing was shown for the first time live on the BBC in November 2010, when it screened the first GB Amateur Boxing Championship. And for every high-profile woman in the ring, there seems to be a queue of equally high-profile naysayers who would rather the ban had never been lifted.

Even fellow athletes have been less than supportive. British boxer Amir Khan, an Olympic silver medallist, said in 2009: "Deep down I think women shouldn't fight. That's my opinion. When you get hit it's very painful. Women can get knocked out."

But the main problem people seemed to have was not one of safety, but aesthetics. The idea of women punching women was, the critics said, unnatural. The boxing promoter Frank Warren waded in following the 2009 announcement of the sport's inclusion in the Olympics, saying: "I am still not a fan of female boxing. I don't like watching women fight for the same reason I don't watch male synchronised swimming: they are not built for it."

When she heard the news that women's boxing would at last make it into the Olympics – and that this would be not just any Games, but an Olympics in her home country – Coulson was ecstatic. She knew this could be her final chance. By 2016 she will be 33 and just months away from the recommended retirement age of 34.

Back in 2009, she was an obvious front-runner for 2012. Unlike the men, who can enter into 10 different weight categories, there are just three for the women, as it is a newer sport. These are: flyweight (48kg to 51kg), lightweight (57kg to 60kg) and middleweight (69kg to 75kg). Coulson fitted squarely into the middle category and there was no one else too close to her in ability: the four-time English champion and three-time EU silver medallist seemed to have a clear run to 2012. But then two younger athletes in the same weight started coming up behind her: ex-footballer Natasha Jonas, now 27, and former kick-boxer Chantelle Cameron, 20. All three girls have made it on to the elite GB boxing squad, along with Nicola Adams and the middleweight Savannah Marshall.

Since April 2010 the five have been training full-time together in Sheffield. From Monday to Thursday they live at the Premier Inn opposite the stadium and barely ever get time alone; they live in twin-rooms to cut costs, taking it in turns to sleep in the single room. Their entire day is taken up with training and meetings with the squad's army of experts, including a full-time nutritionist; two physiotherapists; a team doctor; a sports psychologist; a strength and conditioning coach; two performance analysts; anda performance lifestyle adviser. With just five months to go, the tension is palpable, as the boxers fight each other for a place in the final team.

Like the others, Coulson has made many sacrifices to do this full-time. She is on a two-year break from working in the call centre for Cleveland Police and has taken a "massive" pay cut. She's found local companies in Hartlepool to provide sponsorship, but it's still a struggle to pay the mortgage and bills. Some of the athletes get as little as £5,000 a year to commit to this and don't have time to work. The maximum grant for a GB athlete is £27,000 – but that's only for those with serious podium potential.

In a few weeks it will be decided who will go to the Olympic qualifying contest in May, at the World Championships in Chongqing, China. In the fly and middleweight categories Adams and Marshall were so far ahead of the competition that they are the only women in the squad for their size, so they go to the qualifiers automatically. But since only one Brit from each category can go, two of the lightweights will see their hopes of competing brought to an abrupt end.

At the moment, Jonas is edging ahead as the favourite – and Coulson can see her long-dreamt-of chances of competing in 2012 slipping away. "I'd be devastated if I didn't get through," she says. "I've put my heart and soul into it. I've got to put in maximum effort to make sure I'm the one. Because it's the first year female boxing has been at the Olympics it would mean so much. It was always my dream."

Putting on her toughest expression, Coulson describes the current standings: "Between now and May we have to stamp our authority. We've just been in Brazil and we've all lost one fight and won one. Natasha is going to Bulgaria [to compete in the Strandja Cup, where she beat world champ Cancan] – that will give her an opportunity to stamp her authority."

Her words sound aggressive, but are delivered quietly and with a wistful expression, almost as if she's trying to talk herself into the aggression needed to force herself into the team. In fact, none of the girls seems to fit the stereotype of the pumped-up fighter at all; they're more like five friends hanging out at the gym.

"People think you're aggressive and brawl outside of boxing, but the GB girls aren't like that," adds Coulson. "It's a game of skill; not handbags at 10 paces. It's physical chess." But not all female boxers are so accommodating. "You do get some with a chip on their shoulder who are aggressive. There was a girl in Brazil we were sparring with who wanted to knock us out, but technically we were better and had more skill. A boxer beats a fighter any day."

Savannah Marshall, 20, is Britain's big hope in the heaviest weight category. She was 13 when she went to her first competition in Hartlepool. "From then I was hooked and it became my life," she says. "I hate losing." Her main task at the moment is one many women would balk at: gaining weight. "I've just moved up a weight and it's taken me a while to get there. I'm now in the 69kg to 75kg group. I'm still not there – [I'm at 75kg, but] ideally I'd want to be 77kg and coming down to 75kg to compete. I was just starting to struggle [to keep it down to] 69kg, so I've been moved up. It's mostly strength work. It's taken me a year-and-a-half to get where I am. In a way, I've found it harder than losing weight."

The rules for women's boxing are almost exactly the same as for men's. Though there is no equivalent to the "below the belt" rule to protect women's chests – instead, they wear protectors not unlike the groin pads men wear – the only other differences are in the number of weight categories and the lengths of fights. Instead of the three bouts of three minutes practised by the men, the women compete in four two-minute bouts. Rob McCracken, performance coach for the GB team, says this ensures the rounds are more about skill than brute force.

McCracken believes that prejudice against the sport has waned as the sport itself has matured. "I don't see opposition to it now. There are better women coming through and a stronger pool of boxers. A few years ago there were a few objections from people feeling that k women hitting each other was an issue. But once you watch the ability of some of them at the World Championships you wouldn't know, standing a few yards back, whether you were watching men or women."

This is Natasha Jonas's second career in a sport traditionally dominated by men. As a teenager, she was a semi-professional footballer, with trials for the England team and a scholarship to an American university to play. But six months into the scholarship she tore her cruciate ligament and the funding was cancelled, forcing her to return to the UK. "I was heartbroken that it hadn't worked out in football," she recalls. "I had my heart set on it."

Back home in Liverpool she was training in her uncle's karate gym when a woman approached her about a girls-only boxing night. Success followed quickly, and six years on, she is, as Coulson knows only too well, the most likely GB contender for her weight group. "I never thought I'd get this far," says Jonas. "I had just wanted to get back in the gym. Many of the girls seem to have fallen into the sport as a way to keep fit."

Jonas is becoming a poster girl for the sport because she challenges many of the preconceptions some have about it being butch and aggressive. With a slim physique, honey-coloured skin, dazzling green eyes and long eyelashes, she could have had a career as a model. "People say it's a dangerous sport but I had more injuries playing football."

Her family are supportive, though some find it hard to watch. "My mum and dad see me when they can but my nan doesn't any more. She doesn't want to see me get hurt. She felt she had to go when I fought in Liverpool. It was England versus Ireland and she cried when the national anthem played. My uncle said she closed her eyes during the rounds and would only look up each time they finished."

Jonas was working as a customer adviser for an insurance company when the England call-up came. She had already won two national contests. She called her boss to ask for more time off for a competition and was given an ultimatum. "They said, 'If you don't come in, don't come back.' So I said, 'Fine,' and I never went back."

As the squad carries on pummelling the punchbags, a coach bellows, "High tempo now," and their fists begin to blur, their expressions fixed on the bags in front of them. Behind them a poster reads, "This could be you: London 2012 Gold." Now, for the first time, an Olympic medal is more than a distant hope: it's a real possibility.

A brief history of women and the Olympics

False start

The ancient Olympics, taking place in Greece from 776BC, were not female-friendly: women didn't compete, and only the priestess of Demeter could watch. There were games specifically for ladies – held in honour of the goddess Hera – but they comprised just one measly event: a foot-race that spanned five-sixths the length of the stadium track.

Over the first hurdle

There was a loophole, however: though a woman couldn't enter herself, she could enter horses. A skilled breeder and trainer, the Spartan princess Cynisca, employed men to race them for her, winning the four-horse chariot event in 396BC and 392BC.

A marathon, not a sprint

The first modern Olympics were held in Athens in 1896, but still women were not allowed to enter (organiser Baron Pierre de Coubertin, below, thought the inclusion of the fairer sex would be "impractical, uninteresting, unaesthetic and incorrect"). One Greek woman, Stamata Revithi, disagreed, and ran the 40km marathon on her own anyway – an achievement that went unrecognised.

Game, set and match?

The 1900 Summer Olympics in Paris were the first to allow ladies to compete. And the first winner was Ealing-born Charlotte Cooper, a tennis player who triumphed in the women's singles. It was hardly a level playing field yet, though – in 1904, a modest Games held as part of the World's Fair in St Louis, featured 645 men... and just six women.

The Olympic ideal

The first film to be made of the Games was of Berlin 1936, by Leni Riefenstahl. While her innovative documentary Olympia set a standard for filming sporting events, it also had a more sinister function as Nazi propaganda.

Vaulting ahead

At Tokyo 1964, Soviet gymnast Larisa Latynina set the (still-standing) record for most Olympic medals won by an individual. She holds 18, including nine golds – four won in 1956 in Melbourne, three in Rome in 1960 and two in Japan.

Reduced field

Gender discrimination at the Olympics has been surprisingly enduring: as recently as 1992 some 35 countries entered only male athletes.

Late entry

Muslim countries have been slow to field female sports stars, although this is changing. In 1996, Iran was represented by Lita Fariman in shooting. And sprinter Robina Muqimyar and judo athlete Friba Rezihi competed for Afghanistan in 2004.

The red flag is up...

Saudi Arabia, Brunei and Qatar have never sent any female athletes. In 2010, the Olympic committee announced they would "press" these countries on the issue. Qatar promised to send "up to four" female contestants to London. Saudi Arabia, however, has not allowed women to compete; human-rights campaigners have argued the country ought to be banned from the Games.

Free rein

With the addition of women's boxing, there are now no men-only events. But there is only one sport where men and women compete with each other: equestrian disciplines.

Holly Williams