Correction appended December 10, 2008

The UK has drawn fire from UNESCO, the United Nation’s cultural agency, for failing to adequately protect seven of its 27 World Heritage sites from the effects of development.

Photo ' Atlantide Photography/Corbis (top); Douglas Pearson/Corbis (above).

UNESCO says Westminster Abbey and the Tower of London are threatened by development.

The warning, issued by UNESCO’s World Heritage Committee after its annual meeting in July, triggered a review that could lead the agency to label the sites as endangered. If sufficient action is not taken, the sites could be removed the World Heritage List.

UNESCO’s warning concerns icons such as the Tower of London, over which Renzo Piano’s London Bridge Tower, aka “The Shard,” would loom. The 1,017-foot skyscraper, scheduled for completion in 2012, would be the tallest building in the country.

Also of concern are sites in Edinburgh, Scotland. UNESCO says the city’s medieval Old Town is threatened by the scale and character of the Caltongate mixed-use project, master planned by Allan Murray Architects. The agency says it wasn’t given early notice of the project, which involves the demolition of several buildings. “It’s best if they approach us beforehand so that we can recommend adaptations if necessary to ensure the universal value of the site,” says Mechtild Rossler of the UNESCO World Heritage Centre in Paris. 

The agency also warned that new projects in Bath, a World Heritage City about 115 miles west of London, could jeopardize the historic character of the city center. Other threatened sites include Stonehenge and Avebury, Neolithic ruins at Orkney, Liverpool’s Maritime Mercantile City, and famed structures in London’s Westminster borough (Westminster Palace, Westminster Abbey, and St. Margaret’s Church).

There are 878 World Heritage sites around the globe, ranging from castles to national parks. The UK’s 27 sites are found throughout England, Scotland, Wales, and Northern Ireland. As one of 185 World Heritage Convention signatories, the country is charged with creating management plans for the sites, monitoring their conditions, and reporting findings to UNESCO. Objecting to recent project approvals and critical of some management plans, UNESCO dispatched inspectors to London, Edinburgh, and Bath, in addition to requesting status reports on all seven sites from UK authorities.

“It’s a bit embarrassing that we’re in this position,” says Richard Brookes, spokesman for London’s City Hall. London has traditionally guarded the view corridors around landmarks but recently approved high-rises that some contend will compromise key sight lines. The city is revising its policies in consultation with UNESCO, although it won’t revisit existing construction permits, according to Brookes.

The UK is not alone in feeling the heat from UNESCO. The agency also noted development threats in Mexico City and in Moscow, around Red Square and the Kremlin. A growing percentage of sites added to the World Heritage list each year are in urban centers, and protecting them can be difficult, says Rossler, who stresses that UNESCO is not opposed to all new development. Next year, the agency plans to release guidelines to help countries better protect sites in urban settings. 

Correction: Allan Murray Architects is master planning the Caltongate project in Edinburgh. Gensler designed the initial scheme.