BBC director-general Mark Thompson signed off the final broadcast from the corporation's historic Bush House on Thursday, praising it as an "enduring beacon of truth and objectivity".
The World Service, which has made its home at the imposing central London building for more seven decades, has moved to new purpose-built studios.
And Mr Thompson himself featured in the final bulletin at noon on Thursday.
He told listeners: "This benign Tower of Babel, the scene of so many great broadcasting moments and the home of so many great broadcasters over the years, is now silent. Its corridors deserted; its studios empty.
"As the BBC's director-general, I'd like to pay tribute to all those who made Bush House such an enduring beacon of truth and objectivity in a troubled world and I'd like to thank everyone who's tuned in over the years.
"The World Service's London base may be changing, but the BBC's commitment to serve our audiences around the world remains as strong as it's ever been."
And he rounded off his report in traditional style by adding: "This is Mark Thompson, BBC News, Bush House."
Newsreader Iain Purdon pointed out that the World Service lives on, "just not from here".
The service, admired around the globe, has moved into a new home located in an extension to Broadcasting House.
The corporation first took up residence in Bush House in 1941 when its European services had outgrown a temporary HQ in Maida Vale, at a converted ice rink.
Mr Thompson said: "In the decades that followed - as the Second World War gave way to the Cold War and then to today's complex world - Bush House became a unique icon of authority and trustworthiness in news to millions of listeners around the globe.
"Often the World Service and the BBC's language services were the only source of reliable information available to listeners. In some countries that's still largely true today.
"But now the BBC is leaving Bush House for a much expanded Broadcasting House, little more than a mile away, a gleaming new digital centre full of the latest technology and its own proud broadcasting heritage," he went on.
The foreign service was originally based at Broadcasting House when it launched in 1938, but moved out as a result of bomb damage.
Bush House, situated between The Strand and Aldwych, had only ever been leased by the BBC. The property first opened in 1925 and was said to be the most expensive building in the world, costing around £2 million.
It was the base for General Charles de Gaulle's messages of support for the Free French movement when France was occupied by the Nazis during the Second World War.
The various BBC services have been moving out of Bush House since March.