In a studio at Morley College in south London, a group of teenagers are learning how to stand. Some postures naturally convey authority; something as basic as a different way of walking can establish the impression of control. The first time a conductor meets an orchestra, first impressions are all-important; she has, after all, to persuade a large group of musicians to follow her instructions.

That’s right: her instructions. Last year Morley College initiated an introductory course at which young female music students could have a try at conducting for the first time. The event was among a number of constructive responses to increasing anger about the under-representation of women in parts of the classical music world.

Andrea Brown, Morley’s director of music, says that results have exceeded expectations. “It was moving because we had 16- to 19-year-olds, gifted musicians nominated by junior conservatoires, who hadn’t even thought about conducting before,” Brown says. “Some of them loved it – and it was a feeling of liberation for them, realising that they could do it.” The course has just won funding from Arts Council England to allow it continue its work.

The upswing continues this week. And it is needed: if there’s a widespread perception that classical music lags behind the other arts in terms of women’s representation, that is probably because so much of its work is dominated by compositions written in past centuries, which, inevitably, were mainly by men. Now, to coincide with International Women’s Day on 8 March, and the Women of the World festival at the Southbank Centre in London, BBC Radio 3 has created a programme focused on women in music, culminating in a Composer of the Week series devoted to five female composers under 35. It is an opportunity to celebrate women’s musical achievements and bring their work to a wider audience at last.

When Marin Alsop became the first woman to conduct the Last Night of the Proms two years ago – from a podium festooned with pink balloons and a banner proclaiming “IT’S A GIRL” – she expressed astonishment that today there should still have to be a first anything for women. Interviewed on Radio 4’s Desert Island Discs, she recalled telling her music teacher she wanted to be a conductor, only to be informed: “Girls don’t do that.”

When the head of the Paris Conservatoire, Bruno Mantovani, declared, also in 2013, that conducting could be too “physically demanding” for a woman, and the Russian conductor Vasily Petrenko allegedly said that a girl on the podium might distract male musicians, the outrage machine went into overdrive.

Times were ripe for change. With hundreds of years of male-dominated music forming the bedrock of the repertoire, though, campaigners for a more equal music world have a tough battle on their hands. It’s excellent that Radio 3 is spotlighting International Women’s Day – but it is not before time.

A few months ago I chaired a discussion for the British Academy of Songwriters, Composers and Arrangers (BASCA) at which a panel of seven composers – all female, and each born in a different decade – discussed their experiences of building a career in what is still very much a man’s world. Radio 3 was hauled over some red-hot verbal coals. The composer Judith Bingham said that she keeps tallies of how many pieces by women the station plays each week, trawling through listings in the Radio Times. “If you’re lucky there may be one; sometimes there’s nothing,” she says. “It’s like women just don’t exist.” The disapprobation that audience and speakers poured over the radio station was exceeded only by the derision that greeted a passing mention of Classic FM.

It seems that Radio 3, at least, has woken up. According to its editor, Edwina Wolstencroft, who programmed the International Women’s Day focus, the idea came first from the audience, with many responses to a call for ideas for a Composer of the Week anniversary asking to hear more music by women.

“There’s an audience appetite and curiosity,” Wolstencroft says, “and I think we’re going to continue the momentum. Feminism seems to be taking off now in many different ways. People are becoming more vocal about the neglect of women’s voices in all parts of life, and there seems to be a huge boost to women expressing themselves creatively and politically. We have to lift the lid on women composers who have been neglected in many, many respects and shine light on them.”

The first step is to raise awareness, according to the Radio 3 presenter Sara Mohr-Pietsch. In the series Composers’ Rooms, each week she talks to a different composer in his or her creative space. She discovered that, among six major music publishers, the proportion of women composers represented ranged from about 17% down to barely 4%.

“I realised that if we looked primarily at the publishers’ lists, not only would we end up with primarily men, but they’d be people of a certain age, people of a certain background and people who compose in a certain way,” she says.

“Looking at gender meant we had to open up a whole other avenue of inquiry. We’ve ended up with not just more women, but a lot more young composers, many of whom are forging their own paths. There’s a very rich seam of creativity and we only found it because we paid attention; we got serious about what we had to do to find more women. And the quality of the series went up because we talked to a greater diversity of creative people.”

It’s not as if women have not always composed and performed music. One of the earliest composers whose works are still heard today is St Hildegard of Bingen (1098-1179). During the baroque era Barbara Strozzi (1619-1677) became a prolific composer of secular vocal music in Venice; in France, Élisabeth Jacquet de la Guerre (1665-1729) was a celebrated harpsichordist who dedicated a substantial volume of her own music to King Louis XIV.

But those examples were in sharp opposition to the norm. “I’m sure that, had women had the same opportunities to compose over those centuries, there would be an equal number of masterpieces by women,” says Mohr-Pietsch. “They didn’t have the opportunities that composers need to study and improve. Mozart was born a genius, but it took many years, a lot of contact with musicians and a lot of public performances for him to reach a point where he was writing masterpieces.”

Mozart’s sister, Maria Anna – known as “Nannerl”, was a fine performer as a child, paraded around Europe by their father, Leopold, alongside little Wolfgang, but her success was neither expected nor permitted to extend to an adult career. Felix Mendelssohn’s sister, Fanny, was also naturally inclined towards music; again, encouragement came there none. Recordings of her works reveal them to be enjoyable, yet perhaps underdeveloped.

The same is true for Clara Schumann’s compositions, which were mostly written while she was in her teens. Trained as a child prodigy by her ambitious father, she became a celebrated virtuoso, but her career was interrupted by her marriage to Robert Schumann. After he was confined to an asylum in 1854, and died two years later, Clara had to support their seven children on her own. She resumed performing and spent the rest of her life as one of Europe’s most sought-after pianists and teachers.

“The music world has been happy to have female performers – the female as muse, or as conveyor of male genius – for a long time,” says Wolstencroft. “But owning authority and power in public is another matter. That’s where female conductors have had a hard time. Our society is more resistant to women being powerful in public than to women being entertaining.”

There is a darker side to male authority and power in music. A couple of weeks ago the early music conductor Philip Pickett was sentenced to 11 years in jail for raping female students at the Guildhall School of Music and Drama in London in the 1970s and 80s; and ongoing investigations of historic sexual abuse at specialist music schools have spotlighted similar instances. Many female musicians hesitate to speak up about their experiences for fear of losing work.

One conductor who prefers to remain anonymous alleges that when she was starting her career, twice she found her scheduled concerts being cancelled by the person who had organised them after she refused to sleep with him. Other young women instrumentalists auditioning for maestros have sometimes told me horror stories about being pounced upon in the lift, or about an initially positive reaction amounting to nothing after another kind of approach was refused. Some gay men say they are similarly propositioned.

The fear of speaking out prevents the exposure of shockingly sexist attitudes. One excellent young female pianist, who also asks to remain anonymous, has been looking for an agent. “On two occasions I’ve been turned down by big agencies because – and they told me this – they think I will get married, stay home and have babies,” she says. “If you look at the pianists represented by these agencies, a tiny proportion are women. Promoters say it’s easier to sell the men. The piano world is small. People fight for space like animals in the jungle, and those making the best careers are mostly very nice boys.”

Strangely enough, today’s successful violin soloists seem to include more women than men – but a quick look reveals that many are thin and photogenic. That doesn’t mean they are not superb musicians; but it suggests that perhaps non-musical concerns are taking precedence.

The British violinist Tasmin Little says she worries about the effect of over-sexualised marketing on the profession in general. “It can work against some women that if they don’t conform to accepted stereotypes about how one should look, then soloists who might be thought less attractive or slightly overweight might not be considered, in an environment where looks are almost as important to some promoters as the way one plays,” she says. “I think this is becoming more and more an issue to fight against. Music has to be about how people play.”

Orchestras in the US have found a particular way to tackle gender bias when appointing new players. About 20 years ago, many introduced “blind” auditions, asking applicants to play behind a screen – and take off any cloppy high-heeled shoes – so that the playing alone could be judged. According to the latest research from King’s College, London, the result was a 25% increase in the number of women appointed.

But while instrumentalists seem to have innumerable battles on their hands, elsewhere there is real progress – notably the growing number of composers who are women and are creating fresh, new voices. Anna Meredith is active not only in the classical genre, but in pop and film, too. “I was a student in the 2000s, when things were opening up in terms of what might inspire you, what kind of pieces you might write and what you might want to write about,” she says. “I was lucky to be part of that broadening of influence and language. Today the thing I’m most keen on is supporting young teenagers who need a role model.”

Whatever the field, role models function at a deep psychological level – and for female composers and conductors, these figures have been lacking until recently. That has begun to change. The composer Dobrinka Tabakova, whose work features in the Composer of the Week series, agrees: “My first composition teacher was a woman,” she says, “and later I studied with Diana Burrell. When I was a teenager there were already strong female voices like Sofia Gubaidulina, Judith Weir and Kaija Saariaho. The fact that they were forging individual paths made me think it was a possible thing, though I never questioned it because I’d had role models all the way through.

“Our generation is very grateful for the trailblazing path of the generation before us,” she adds. “They’ve done a great deal to make themselves more visible and more heard, and my generation is building on those achievements as women composers. In the past there was a great discrepancy of numbers, but now it’s the best it’s been. I hope it will continue to be that way.”

It is up to Meredith, Tabakova and their colleagues, and the young girls of the Morley College conductors’ course, to carry the torch. By asserting themselves, building careers and reaching ears, minds and imaginations, they are also opening up a field that can look closed and reactionary – and not only opening it to more forward-looking attitudes, but potentially to a new audience for a new era. Let’s hope that the Radio 3 series is the start of great things.