Abolishing the international development department would undermine Britain’s reputation as a leader in overseas aid, Rowan Williams, the former Archbishop of Canterbury, has warned.

In the latest sign of concern over the future of the Department for International Development (DfID), Williams said that reducing its work to “a subdivision of general foreign policy”, which used foreign aid to assist Britain’s security aims, would be a “damagingly short-term” decision. It comes amid continuing rumours in Whitehall that Boris Johnson will fold DfID back into the foreign office - something he advocated during his time as foreign secretary.

His senior adviser, Dominic Cummings, is understood to be drawing up radical plans to shake up the structure of Whitehall.

Williams told the Observer: “In spite of a lot of ups and downs, DfID has long been crucial to the UK’s reputation as a global leader in the funding of overseas development. Reducing this to a subdivision of general foreign policy, rolling up development grants into what can be simply ‘security’ or anti-terrorist funding by another name, is to accept a damagingly short-term perspective in a world where economic stability and independence are the best long-term guarantees of shared security worldwide. Only an intelligent engagement with building grass-roots self-reliance will deliver this, freed from the pressures of instant national self-interest on our part.”

UK aid risks becoming a vehicle for UK foreign policy Coalition of charities

A coalition of charities has already sounded the alarm over the department’s future. The group, which includes the British Red Cross and Oxfam GB, warned that abolishing it would suggest Britain is “turning our backs on the world’s poorest people”. They warned: “UK aid risks becoming a vehicle for UK foreign policy, commercial and political objectives, when it first and foremost should be invested to alleviate poverty.”

Several Tory figures have also expressed concern, including Alistair Burt, a former Foreign Office and development minister, and Andrew Mitchell, a former development secretary. It comes after the growing use of the aid budget on issues designed to combat terrorism. About 30 per cent of the £14bn annual aid budget is now spent in departments outside DfID.

Both No 10 and DfID have refused to comment on speculation about the department’s future. No plans to reform DfID have been announced so far. However, Johnson, as foreign secretary, pushed for control of DfID and its multi-billion pound aid budget. Johnson argued earlier this year that the aid budget should be “more in line with Britain’s political commercial and diplomatic interests”.