The Oxfam sex abuse crisis deepened last night after it emerged that British aid agencies were warned 10 years ago of an “urgent problem” and the Haiti president accused charities of covering the attacks up.

A report presented to charities in 2008 claimed that children as young as six were forced to sell sex to aid workers in exchange for cash, food and mobile phones.

Oxfam's chief executive admitted today the organisation should have been more open about allegations of sexual abuse by its workers in Haiti.

Mark Goldring said the charity needed to "win back the trust" of the British people.

"We are sorry for the mistakes we have made," he wrote in a column in the Sunday Mirror.

"We should have been more open with the public about the fact that staff in Haiti were fired for sexual abuse. And we should have expanded our safeguarding team faster."

He added: "As an organisation that fights for women's rights, the abuse of women in Oxfam's name is particularly hard to bear."