DfID has faced criticism over its reliance on private sector consultants – dubbed poverty barons – who were paid almost £500million last year.

'Suppliers must show they’re not just in it for the money,’ said a Whitehall source.

'In the next few weeks Justine will get all our top suppliers in for face-to-face meetings to explain that the department will be looking for better value for money in new contracts.

'If they can’t deliver better value, we’ll use suppliers who do.'

Miss Greening is also insisting on personally signing off IT and buildings deals worth more than £500,000.

She was appointed International Development Secretary last month at a time of renewed criticism of the Government’s plans to pour billions more into foreign aid in the coming years.