Plans by the Government to make it easier for ministers to appoint their own candidates to run public bodies would result in Britain’s institutions being led by a narrow clique of “white, male” insiders, the man in charge of overseeing the system has warned.

Sir David Normington, the Commissioner for Public Appointments, said diversity would suffer and ministers would face charges of cronyism if the Government signed off on a recent review by Sir Gerry Grimstone, the deputy chairman of Barclays. The review recommended sweeping changes to the way public sector officials, such as the head of the Bank of England, are hired.

Approving the plans would mark a return to the bad days of Whitehall appointments, Sir David added. The system was reformed following recommendations by Lord Nolan’s Commission on Standards in Public Life after a string of sleaze scandals in the 1990s.

Writing for independent.co.uk, Sir David said: “Grimstone’s proposals would enable ministers to set their own rules; override those rules whenever they want; appoint their own selection panels; get preferential treatment for favoured candidates; ignore the panel’s advice if they don’t like it; and appoint someone considered by the panel as not up to the job.

“The main check on these powers is transparency, but that has its limits when no one has the power to intervene if the rules are broken.”

Sir David, who steps down from his role at the end of the month, added that public appointments to bodies such as the media regulator, Ofcom, carried huge power and responsibility.

“Public bodies spend billions of pounds of public money and touch every aspect of people’s lives – in education, health, justice, the arts and sport,” he said.

“Their boards need to be effective and diverse. Candidates must be confident that they will be fairly treated – otherwise they won’t apply.”

Matthew Hancock, Minister for the Cabinet Office, said the Nolan principles would stay “at the heart of the system”. But he added: “Ultimately, choice, responsibility and accountability for making appointments must rest with ministers.”