The charity watchdog is to begin its inquiry into Oxfam following the aid worker sex scandal which resulted in the resignation of one of its most senior figures in the UK.
Oxfam issued an "unreserved apology" to the government, donors, supporters and the people of Haiti over its handling of sex allegations, including the use of prostitutes by workers in Haiti in 2011.
Announcing her resignation as deputy chief executive, Penny Lawrence said she took full responsibility for what had happened on her watch and was sorry for the "harm and distress" it had caused supporters, as the charity faced a battle to "rebuild the public trust" following crisis talks with the Government over future funding.
The watchdog said Oxfam may not have "fully and frankly disclosed material details about the allegations at the time in 2011" and it also had concerns about its handling of the incidents since, and the impact that these have both had on public trust and confidence.
The commission's deputy chief executive David Holdsworth said: "Charities and dedicated, hard-working aid workers undertake vital, lifesaving work in some of the most difficult circumstances across the world.
"However, the issues revealed in recent days are shocking and unacceptable. It is important that we take this urgent step to ensure that these matters can be dealt with fully and robustly."
The commission's inquiry came as:
- Helen Evans, Oxfam's former global head of safeguarding, told Channel 4 News she begged senior staff, ministers and the regulator to act about the sexual abuse allegations.
- International Development Secretary Penny Mordaunt told Oxfam they "must now demonstrate the moral leadership necessary to address this scandal, rebuild the trust of the British public, their staff and the people they aim to help, and deliver progress on these assurances".
- Oxfam's chief executive Mark Goldring said he would not stand down unless the charity's board told him they had lost faith in his leadership.
Ms Evans detailed three new allegations made against Oxfam staff overseas in a single day.
She said: "There was one of a woman being coerced to have sex in a humanitarian response by another aid worker, another case where a woman had been coerced in exchange for aid and another one where it had come to our attention where a member of staff had been struck off for sexual abuse and hadn't disclosed that, and we were then concerned about what he might be doing, and that was three allegations in one day."
Mr Goldring apologised to Ms Evans over the way her concerns were handled.
He told Channel 4 News: "I certainly apologise for not acting fast enough, I think we did take them seriously and we responded on many different fronts - the records checking was one of them, training was another, the promotion of the helpline was another - she did some great work.
"What I recognise now, with the severity of issues as they have emerged, is that we should have resourced that team up faster as we now have, indeed, done."
He said he would not resign as he was not in the post in 2011, and added: "But if our board turn round and say 'actually you are not the right person to lead forward' then I of course would resign immediately."
Following a meeting between Oxfam bosses and International Development Secretary Ms Mordaunt, the minister said: "I was clear that part of an organisation's moral leadership comes from individuals taking responsibility for their actions."
The charity's chair of trustees Caroline Thomson said Oxfam "unreservedly apologised to her (Ms Mordaunt) as well as to our supporters, donors and the people of Haiti for the things that happened in our name".
Announcing her resignation, Ms Lawrence said: "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."
The resignation comes after claims on Monday that the charity was aware of concerns about the conduct of two of the men at the centre of the allegations in Haiti when they worked previously in Chad.
The charity received £31.7 million in Government funding in 2016/17, but the support has been put at risk by the scandal.
Four members of Oxfam staff were dismissed and three, including the country director - Roland van Hauwermeiren - resigned before the end of the 2011 investigation.
According to The Times, Oxfam knew about concerns over the conduct of Mr van Hauwermeiren and another man when they worked in Chad before they were given senior roles in Haiti.