UNESCO has called on the UK government to demand changes to Edinburgh’s planning system in order to preserve the Old and New Towns, two of six UNESCO sites in Scotland.

Mechtild Rössler, director of world heritage at UNESCO, had “strong concern” about urban conservation in the capital, citing worries including the “ribbon” hotel in the St James development.

In a report sent to the Department for Culture, Media and Sport in November, but which has only come to public attention now, it said “current planning and approval paradigms should be revised”.

Dr Rössler’s letter was described as significant by James Simpson, a member of the UK committee of the International Council on Monuments and Sites.

He said: “Icomos-UK has made modest suggestions about how might work with regard to design briefs and impact assessments: these should not simply be prepared by the developer.

“Developers are paying the piper and calling the tune. These kinds of reports must be prepared independently and report directly to the planning department.”

He added that planning officials on Edinburgh council’s planning committee who advised against the new St James Hotel were defeated by “a renegade mob”.

“Short-term economic benefit outweighs all other criteria,” he said.

“Decisions need to be made in regard to the long term, and with regard to social, cultural and environmental criteria as well as purely economic criteria.

“Going for the short-term economic benefit might be counterproductive in the long term. There will be an element, especially where tourism is concerned, of killing the goose that lays the golden egg by demeaning the city.”

A proposal to convert a building to offices on West Register Street was passed by the council but was “called in” last week by the Scottish Government on Historic Environment Scotland’s advice.

The proposed build, “Registers”, is being promoted by the Chris Stewart Group, which is responsible for the refurbishment of Advocate’s Close.

However, the changes to that part of the Old Town have come under fire.

One campaigner said: “It’s seen as a success by developers and in the building industry but I don’t think Advocate’s Close is seen as success by conservationists. It’s commercially successful, but the new bits are not of a high enough quality; it’s not properly detailed.”

Nicholas Hotham, head of advocacy for the Edinburgh World Heritage Trust, welcomed the intervention by UNESCO.

He said: “Three main issues have been raised: the visual integrity of the city; the impact of major buildings; and the governance structure.

“We do need to deal with those.”

Alison Johnstone, Scottish Green MSP for Lothian, has urged the City of Edinburgh Council and the Scottish Government to act upon UNESCO’s concerns.

Alison spoke at the recent planning hearing into the Old Royal High School development, warning that Scotland’s capital city was at risk of damaging a key aspect that makes it so special - its historic built environment.

Ms Johnstone said: “This report is a wake-up call for local and national government. We have a developer-led system that leaves our fantastic built heritage vulnerable to inappropriate development.

“There is a balance to be struck to ensure Edinburgh is a city that works for local people but also continues to draw visitors from around the world. The way that new developments are handled is clearly causing concern at UNESCO and the threat to our world heritage status must be taken seriously.

“Our capital city needs a clear plan for how to make best use of potential development sites in a way that adds to our unique qualities, rather than detracting from them. There are certainly examples of good practice we should be using as inspiration. New housing and economic activity is vital but as these comments from UNESCO show, the scales are being tipped too far in favour of development driven purely by profit.”