One in seven aid charities taking taxpayers’ money to spend abroad have now reported conduct breaches, with dozens of new claims of abuse, including paedophilia, the International Aid Secretary has said.

Penny Mordaunt said Monday at a summit in London that some of the UK’s biggest charities are now embroiled in the sex abuse and harassment scandal engulfing the sector, but their names will not be automatically revealed.

It has been more than three weeks since it emerged Oxfam workers delivering aid after the 2010 Haiti earthquake had paid for sex. The revelations have led to fresh questions over the UK’s massive national foreign aid budget – the second largest in the world.

Last month, Ms. Mordaunt wrote to all 179 aid charities taking public money to spend in the developing world, demanding to be informed of any “safeguarding breaches”.

She revealed Monday that the Charity Commission had been subsequently made aware that 26 of them had reported 80 “incidents” involving a “full spectrum” of abuse.

At the summit, Mordaunt insisted charities wishing work with the government going forward needed “to take this issue as an urgent priority”.

She said: “Now is the time for action. The aid sector needs to ensure it is meeting its duty of care to the world’s most vulnerable people. It needs to be honest about past mistakes. It must do all it can to win back the trust of the British public.

Adding: “My message to those who have sought to exploit this sector and the human tragedy in which it operates is this: we will share all the information we have with law enforcement.

“We will find you, we will bring you to justice, your time is up. This summit is a critical moment to learn lessons and drive up standards across the entire aid sector. Now is the time for action.”

However, the names of suspects will not be made public unless the cases lead to a full inquiry, the investigating Charity Commission has insisted, leading to critics claiming there could be a cover-up.

“We don’t reveal the names of charities reported to us,” a spokesman said, explaining that individual charities would only be publicly identified when a “formal inquiry” was opened.

Baroness Stowell, Chair of the Charity Commission, commented: The recent accounts of sexual exploitation and abuse in the aid sector are deeply distressing.

“Not only have some aid workers abused the people they were sent to support, but by not exposing and responding to these serious failings properly at the time, charities have betrayed the public’s trust in what the word charity actually means.”