You can only hear so many stories before you reach the limit of your own endurance. My moment came on a visit to a refugee camp in Chad, where Hawaye, a beautiful Darufi woman holding her newborn baby, told me hers.

The Jangaweed - armed mercenaries - had ridden into her village, killed her husband and decapitated their baby in her arms. They had taken her captive and kept her as a sex slave.

She had been multiply raped for three weeks before being thrown out, pregnant by one of her many violators, her life effectively destroyed. When she had finished describing the events that had led her to this refugee camp she was the only dry-eyed woman in the hut. I asked her what we could possibly do. "Justice," she said, her dark brown eyes pools of sadness, "safety and a future".

In our world, such ambitions might seem achievable; in hers they exceed even the wildest expectation. The reality for a woman such as Hawaye can be found in a random sampling of facts compiled by The Fawcett Society recently to mark International Women's Day: gender-based violence causes more deaths and disabilities among women aged 15-44 than cancer, malaria, traffic accidents and war.

It is estimated that worldwide, one in five women will become a victim of rape or attempted rape in her lifetime. Of the 250,000-500,000 women and girls raped in the 1994 genocide in Rwanda, the number of convictions produced by the International Criminal Tribunal for Rwanda is eight.

Every year, 60million girls are sexually assaulted at or en route to school. One in four women will be a victim of domestic violence in their lifetime - many on a number of occasions. Some 70 per cent of those under the poverty line are women and with two-thirds of the world's illiterate also being female, taking control of their own destinies is a serious challenge.

For millions, the basic human rights articulated by this traumatised woman are as far from being achieved today as they were 200 years ago.

As my husband will attest, one of my greatest skills is shouting loudly, so along with Moroccan ex-financier and now artist Karen Ruimy, I set up The Great Initiative, a tiny foundation with huge ambitions to draw attention to the plight of women in the developing world and to fund grassroots projects conceived and run by African women.

We were particularly inspired by Femme Africa Solidarité (FAS), whose African Gender Award seems a brilliantly effective way of cajoling African leaders into making women's rights, not normally considered a vote winner, into a priority. The award goes to the leader who has most improved the status and rights of their female population in the preceding year and offers the opportunity to celebrate the many positive changes occurring across the continent.

Which is how Karen and I found ourselves in Liberia celebrating this year's FAS Award winner and Africa's first female leader, Liberian President Ellen Johnson Sirleaf, with the Hollywood actress Renée Zellweger, our newest patron.

Attracting attention to the plight of women can be an uphill struggle but we've been delighted by the supporters we've attracted, from Bono, Damon Albarn and Graça Machel to Ms Zellweger. There are few movie stars that you can call, invite to a recently war-torn African nation and three weeks later find yourself travelling alongside them. "Sounds interesting, count me in," was Renée's texted reply and on the designated date she showed up in London, clad in North Face, rucksack packed and raring to go.

Like us, Renée was fascinated by the story of Johnson's ascent to power, one that's already spawned a brilliant documentary, Pray the Devil Back to Hell.

She said: "I decided to support Great because I was excited by the way they amplify the voices of women whose stories we rarely hear, by their support of the inspirational FAS African Gender Award and by their commitment to fund small grassroots projects conceived and run by African women."

Ellen Johnson Sirleaf lived through two civil wars in Liberia, witnessing how the rebel leader, Charles Taylor, augmented his forces with gangs of feral boys as young as eight, stolen from their families in the night, brutalised, drugged, loaded with weaponry and sent to terrorise their countrymen and women. Rape was at epidemic levels.

During the second civil war, by which time Taylor had become president, a group of Christian women decided the bloodshed had to end. In the Liberian capital, Monrovia, they set up a peace movement - Women of Liberia Mass Action for Peace - and were soon joined by their Muslim sisters.

The Liberian economy depends on its 37,000 farming women, despite their lowly status and lack of rights. But instead of digging, planting and cultivating they took to sitting in Monrovia's main market square, through which Taylor had to pass daily. Their numbers swelled and their white cloth-draped bodies, chanting and singing increased the dictator's embarrassment until Taylor agreed to peace talks.

The talks broke down but the women barricaded the doors, saying it was peace or incarceration. Taylor eventually stood down and these same women led an election campaign that in 2005 brought to power Africa's first female president, Ellen Johnson Sirleaf.

After six years in government, Johnson remains indebted to the women who elected her. "No nation prospers unless there's full recognition of the contribution of women and they are educated and allowed to participate in society," she says. "Where women are empowered the country's economy expands, per capita income is increased, the country's GDP increases and the level of tension in society is reduced. Any country that wants to prosper and to have sustained growth and development has got to empower women."

Her message is clear: invest in women and you can change the history of whole continents.

EDUCATE a woman and you educate a country, goes the Liberian saying, and under Ellen Johnson Sirleaf more women are attending school and the country is now on a trajectory out of desperate poverty with one of the fastest growth rates in Africa.

On our second day in Liberia Renée turned to me with a smile and said in a mixture of awe and amusement: "These women are really fierce!" She spoke for us all as we witnessed them bridge political, religious and tribal divides in their determination to achieve equal rights and build a future for their nation.

Outside the main market in Monrovia we met Hannah Kamara, a woman of 40 who asked to read to me from a junior school primer called "I Am A Worker". She had used her takings from the new women's cooperative to learn to read and couldn't contain her excitement and pride. As we listened to her hesitantly read a story my six-year-old wouldn't struggle with we were truly humbled by her pride and determination to change her destiny.

Our modest ambition with The Great Initiative is hardly controversial. Hannah Kamara deserves an education, she deserves to know that she can turn to the law if she is beaten or sexually violated, she has a right to own the land she works on and receive respect for her fundamental role in contributing to her country's economy.

It is possible to create a world where for Hannah and the market women, my Darufi friend Hawaye and her baby daughter Nadjva and all the millions of women like them whose voices we rarely hear, justice, security and a future are no longer a fantasy but a basic right.