By David Mercer, News Reporter
Actress Minnie Driver is the first celebrity to resign as an Oxfam ambassador in protest at the sex scandal engulfing the charity.
The Good Will Hunting star said she was "horrified" by allegations that some Oxfam staff were having sex with prostitutes in crisis-hit Chad and Haiti.
The news came as it emerged the aid worker at the centre of the scandal, Roland van Hauwermeiren, joined Oxfam after he was dismissed by another British charity over similar allegations of sexual misconduct.
In a statement to The Telegraph, Driver said: "I am nothing short of horrified by the allegations against Oxfam International.
"In no uncertain terms do I plan to continue my support of this organisation or its leaders.
"And though it is unfortunate that after 20 years I am no longer able to advocate and defend through this specific framework, social and economic injustice is more globally prevalent than ever.
"I certainly will not let the abhorrent mistakes of a troubling organisation stop me or anyone else from working with good people in this space to support a population of human beings around the world that needs our help."
Driver, 48, has travelled to Thailand and Cambodia in her role with Oxfam and performed at a charity concert in London in 2004, joining stars such as Chris Martin, Razorlight and REM.
In a statement, Oxfam said: "Minnie Driver has been a devoted Oxfam supporter for many years, and we are grateful for her commitment to ending global poverty.
"Her decision to step down as an Oxfam Ambassador saddens us deeply, but we also understand and respect her choice.
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"As an organisation, we are ashamed by the actions of some of our staff and are more committed now than ever to learn from our mistakes and ensure we uphold the highest levels of safeguarding standards in our work around the world."