January 12, 2011, 9:23 AM EST

By Tim Barwell

Jan. 12 (Bloomberg) — London Underground’s headquarters, the U.K. capital’s first skyscraper, was granted the highest level of protection from demolition because of its “outstanding architectural interest,” the government said.

The building, which houses St. James’s Park subway station, was upgraded to a Grade 1 listing from Grade 2 after a review by English Heritage, the official organization for archaeology, heritage and conservation in England, according to a statement today. The property at 55 Broadway in central London was the city’s tallest office tower when it opened in 1929.

“The daily commute can sometimes prove a dispiriting experience but the next time Londoners use St. James’s Park station, I would encourage them to stop and pause,” English Heritage’s Hannah Parham said in the statement, calling the building “jewels in London’s architectural and historic crown.”

A listed building cannot be demolished, extended or altered without government planning guidance, according to English Heritage’s website. Only 2.5 percent of listed properties are Grade 1 buildings.

–Editors: Andrew Blackman, Eddie Buckle.

To contact the reporter on this story: Tim Barwell in London on tbarwell@bloomberg.net

To contact the editor responsible for this story: Andrew Blackman at ablackman@bloomberg.net