If money is power, the £160bn ($310bn) the government spends annually on buying goods and services from the private sector should give it more than enough clout to impose its values and priorities on suppliers. But the array of differing – and often conflicting – objectives the government has set for public sector procurement is provoking tensions within Whitehall and worrying business.

Public-sector employers can be required to disclose pay disparities between their employees. Now Harriet Harman, the equality minister, is determined to use the procurement process to winkle similar information out of the private sector, requiring companies to reveal the number of women, disabled people and members of ethnic minorities who make up their workforce.