The United Nations is being urged to examine Edinburgh’s controversial £150 million Caltongate scheme.
Major cultural watchdog the International Council on Monuments and Sites is urging heritage site watchdog UNESCO to intervene.
Dr James Simpson of Edinburgh based architects Simpson and Brown, UK vice president of Icomos said strong representations had been made to UNESCO, but admitted talks were at an early stage.
Mr Simpson said he believes the development is wrong for the Old Town and said protecting the World Heritage Site should be a matter of national interest.
He added that it does Scotland’s international reputation harm if it is not seen to manage its World Heritage Sites to a high standard.
Campaigners opposed to the project including leading authors Irvine Welsh and Alexander McCall Smith are also urging MSP’s to raise the issue in parliament.