The Charity Commission has launched a statutory inquiry into Oxfam amid concerns it may not have "fully and frankly disclosed" all details about sexual assault allegations in Haiti in 2011.

The charity issued an "unreserved apology" to the Government, donors, supporters and the people of Haiti following the revelations.

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.

Oxfam CEO Mark Goldring apologises over Haiti sex scandal

Oxfam has faced intense criticism over its handling of sex allegations, including the use of prostitutes by workers in Haiti in 2011.

The Charity Commission launched its investigation after examining documents provided by Oxfam.

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.

Penny Lawrence resigned as Oxfam’s deputy chief executive (Charlotte Ball/Oxfam/PA Wire)

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."

Ms Lawrence's resignation comes after claims 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 £31.7m 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.