Youngsters in crisis zones risk being drawn into extremism and radicalisation unless they can have the opportunity to go to school, Gordon Brown warned as he launched a new global education fund.

The former prime minister and UN Secretary General Ban Ki-moon hope the Education Cannot Wait fund, which received a pledge of 100 million dollars (£69 million) in business backing, will support youngsters hit by disasters and war.

The programme was launched at the World Humanitarian Summit in Istanbul in a session chaired by Mr Brown, the United Nations special envoy for global education.

Mr Brown said: "Without school, young children caught up in emergencies are at risk of becoming the youngest labourers in the field, the youngest brides at the altar, the youngest soldiers in the trench, and in some cases, the youngest recruits vulnerable to extremism and radicalisation."

The fund is aimed at filling the gap between humanitarian aid, which meets short-term needs such as food and shelter, and longer-term development programmes which might not focus on education.

Mr Brown said: "For the first time, we have a humanitarian fund targeting education. A fund that plans - not just for weeks or months - but for years in support of a child's development.

"A humanitarian fund with windows for foundations, businesses, philanthropists and, for the first time, IT companies such that they may contribute funds and intelligence to support refugees wherever they may be found.

"And a fund with a contingency reserve allowing us to act when a crisis hits ensuring no begging bowl has to be circulated."