Penny Lawrence today resigned as deputy chief executive of Oxfam, following several days of negative coverage as the charity was widely criticised over its handling of sexual misconduct in 2011.
Yesterday the charity announced a raft of new measures to improve its safeguarding.
The charity's senior leaders met with the international development secretary and the Charity Commission earlier today, after the Times revealed details of senior staff paying for sex in Haiti. Oxfam has been criticised for not being open enough with the Commission, DfID or the public.
'I take full responsibility'
Lawrence said: "I am deeply sad to announce that I have resigned as deputy chief executive of Oxfam GB.
"Over the last few days we have become aware that concerns were raised about the behaviour of staff in Chad as well as Haiti that we failed to adequately act upon. It is now clear that these allegations – involving the use of prostitutes and which related to behaviour of both the country director and members of his team in Chad – were raised before he moved to Haiti.
"As programme director at the time, I am ashamed that this happened on my watch and I take full responsibility.
"I am desperately sorry for the harm and distress that this has caused to Oxfam's supporters, the wider development sector and most of all the vulnerable people who trusted us.
"It has been such a privilege to work for such an amazing organisation that has done and needs to continue to do such good in the world."
Mark Goldring, chief executive of Oxfam GB, said: "I deeply respect Penny's decision to accept personal responsibility. Like us, she is appalled at what happened and is determined to do what is best for Oxfam and the people we exist to help.
"I would like to place on record my sincere thanks for the years of dedicated service that Penny has given to Oxfam and the fight against poverty around the world."