Scottish heritage groups have applauded Unesco's decision to send a team of investigators to assess Edinburgh's world heritage status.

The groups hope that an intervention by Unesco (United Nations Educational, Scientific, and Cultural Organisation) will halt several planned building projects that they claim will ruin the city's distinct character.

Unesco's world heritage committee decided to send the investigators after hearing, as one insider put it, “something might be amiss in Edinburgh”.

Its initial report is likely to be carried out by February next year, and could result in the city losing its world heritage status.

Adam Wilkinson, director of the Edinburgh World Heritage Trust, said: “We welcome Unesco's move. They are right to pose questions about Edinburgh's status, and we would look forward to any new assessment”

Edinburgh's city centre, comprising the medieval Old Town and Georgian New Town, was designated a world heritage site in 1995, one of 855 in the world and 27 in Britain. Despite the prestige of the award, it does not guarantee statutory protection from unsympathetic development, and a growing list of new building projects and plans in the city have been drawn to the Unesco committee's attention.

These include the £300million Caltongate project, plans to re-develop the St James Centre and the construction of a large residential development at Leith Docks.

Heritage campaigners have focused their anger on the Caltongate scheme, which began as the redevelopment of a bus garage on New Street, but has grown into a much larger project, which extends down East Market Street and breaks into the Royal Mile on the Canongate. The scheme was called in by the Scottish government, but approved last month.

In 2005, Edinburgh World Heritage Trust published a management plan for the area that was endorsed by Historic Scotland and Edinburgh City Council. This made the heritage of the city the touchstone for construction in it, although the plan allowed for redevelopment that took contextual clues from the historic surroundings.At a council planning meeting this year, the trust criticised the Caltongate project as an inappropriate development that would erode the character of the Old Town.

The trust objected to the “the large building footprint of the hotel and offices” and attacked the loss of listed buildings and the use of “facadism” - retention of the outside wall of a building - in the construction of a hotel.

Concerns about public procurement procedures were also raised, particularly over the sale of council-owned land in East Market Street.

Faced with so many voices of disquiet, including about 1,800 individual objections to the Caltongate development, Historic Scotland invited Unesco to visit Edinburgh.

“Historic Scotland and the City of Edinburgh Council are content that the amendments made during the consultation on the Caltongate development removed any threats to the outstanding universal value to the world heritage site,” a spokesman for Historic Scotland said.

Campaigners point to recent events in the German city of Dresden as to how a Unesco visit can make a difference. The construction of a new four-lane bridge was said to compromise the cityscape around the historic Pillnitz Palace. The world heritage committee decreed last Friday that if construction was not stopped, “the property would be deleted from the world heritage list in 2009”.

Linda Fabiani, Scotland's culture minister, was confident that Edinburgh would not suffer a similar fate.

“I believe in the universal values of Edinburgh's Old and New Town as a world heritage site. When the Unesco mission visits our capital, it will see a vibrant, growing city which embraces its heritage as well as managing an improvement in development that benefits Edinburgh as a whole.”

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