Mr Brown is in contact with representatives of 20 countries which he hopes will support this project.

He wants them to provide financial guarantees for loans for education, in the way that financing was used for mass immunisation schemes.

The ambition, says the former prime minister, is to have the first generation in history in which all young people have a chance to go to school.

Access to education, he says, is the "civil rights struggle of our time".

The lack of school places has appeared to be an "intractable problem", but he says that mobilising such funding would provide low-income countries, such as in sub-Saharan Africa, with a way of making rapid progress.

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Current aid levels only provided a fraction of what was needed - when education was "vital to economic success and individual potential".

"We can't get away from the fact that there's an education crisis. This divide has catastrophic consequences," said Mr Brown.

"Instead of being in school, children will be trapped as labourers, brides, soldiers, and victims of trafficking.

"Aspiring doctors, lawyers, teachers, and innovators of tomorrow will never realise their talents - this is a loss we cannot afford."

Mr Guterres said it was not possible to accept so many children "failing to learn even the most basic skills".

"In the coming decade, someone billion young people will enter the workforce. They all need education so that they can help build a world of peace, prosperity, dignity, and opportunity for all."