Julia Gillard, former prime minister of Australia, has revealed her new role as chairwoman of a major international education campaign.
The Global Partnership for Education works to improve education in some of the world's poorest countries in which 57 million children have no access to primary school.
The UK government is the organisation's biggest single donor.
Ms Gillard says "there can be no higher priority" than international education.
Before becoming prime minister, Ms Gillard had been minister of education in Australia.
She became known to a global audience for a searing speech accusing the leader of the opposition of double standards over sexism in public life.
'Fragile countries'
Her new role will be as chairwoman of the Global Partnership for Education (GPE) which is a coalition of governments, private sector and aid organisations working with about 60 developing countries.
It aims to tackle the unresolved problem of a lack of basic education in "the world's poorest and most fragile countries".
There are tens of millions of primary-age children who never get a single day in school of any kind.
Most of these are in sub-Saharan Africa and in parts of Asia. The causes include conflict, corruption, inequality, a shortage of teachers and lack of funding.
"There is much to do and little time," said Ms Gillard.
The former prime minister said the new campaigning role will combine her longstanding interests in education and fair opportunity.
"Education has been my driving passion in public life," she said.
She promised to bring some "Australian bluntness" to the task and said that the world community needed to keep its pledge to provide an education for all children.
"This would be the worst time for efforts to slide backwards," she said.
"Otherwise we will be condemning poor nations to be poor nations forever."
She warned that there had been a sharp decline in donor support and that international aid for education must not become the "poor cousin".
Ms Gillard said that she had no idea how her speech attacking sexism would "reverberate around the world".
"I didn't have any sense that it would take off," she said.
The realisation of the global impact came when she visited India as prime minister and was congratulated by the female police officers on duty.
In her new role, she said she wants to make sure that girls have a fair chance in education.
Waiting 70 more years
A report from Unesco last month said that at the present slow rate of progress it would be more than 70 years before all children could start primary education, with the biggest problem among girls in rural sub-Saharan Africa.
The international community had promised that this goal of universal primary education would be achieved by 2015.
Unesco has warned of the risk of political instability and economic damage when a quarter of young people in poor countries are unable to read a single sentence.
The Washington-based GPE has targeted billions of pounds to support the development of education, helping to increase the number of primary places and to ensure equality of access for girls.
There will be a major "replenishment" process for the GPE in June as this multinational project seeks renewed funding from national governments and foundations.
"The global community must respond generously to the upcoming call for a renewal of multilateral, bilateral and national financing for basic education," says Ms Gillard.
She says that the GPE's approach, with a partnership between those providing and receiving aid, was a "unique and effective model".
In cash terms, the UK is the GPE's biggest funder, followed by Australia, the United States and Norway. Support from the US fell by more than half between 2012 and 2013.
Funding for international education has fallen since the financial crisis - and Unesco has raised questions about whether some international education is targeted at the countries with the greatest need.
The biggest single recipient for education aid is China, which receives support, mostly in scholarships, with a value 77 times greater than aid given to Chad, according to Unesco.
There has been support for GPE's partnership approach from recipient countries.
Afghanistan's education minister, Farooq Wardak, says that the GPE has been an important part in his country's progress in reopening hundreds of schools which had been closed through threats and violence.
The Afghan education ministry says pupil numbers have risen from 900,000 in 2001, with few girls in attendance, to 10.5 million pupils, including 42% girls.
Mr Wardak told the BBC that the progress in education was so embedded it would survive any political upheaval after the withdrawal of international forces.
He promised universal access to primary school by 2020.
Source: BBC