To date, only 26 projects out of 70 approved schemes under the CTF have reported any benefit. The vast majority of the projects do not record any figures at all.

Dfid’s own annual review of the schemes reveals that in 2014 officials were concerned that the CIFs “had been slow” to put in place practices “on carrying out rigorous assessments through evaluation” of its projects. Dfid subsequently authorised spending of £6m “specifically for evaluation and evidence based learning” to address “this weakness”.

A year later in 2015, according to the Dfid review, officials wrote to the World Bank “highlighting our concerns” with aspects of the management of the funds.

The Dfid review, published last year, also raises concerns over delays to projects and “the inability to demonstrate results”.

It is understood that Priti Patel, the International Development Secretary, who was appointed last summer, has demanded some of the climate change programmes be more thoroughly investigated.

A senior Dfid source said: “Ministers have called in a number of climate programmes for close scrutiny to ensure they are on track and delivering.”

The insider added: “The money would be better spent on our humanitarian response with proven results than some of the incredibly complex climate programmes.”