Sources with knowledge of the negotiations said the BBC’s Thai-language output impeded discussions about renewing the 20-year lease on the complex, the network’s main shortwave broadcast station for Asia.

The centre’s large red and white transmission towers in Nakhon Sawan 150 miles (240 kilometres) north of Bangkok beamed local language news into tightly-controlled countries such as China and North Korea, and into places where many still rely on radio like Pakistan and Afghanistan

But it went off air on January 1 following the expiry of the lease.

“Despite extensive negotiations, we have been unable to reach an agreement to re-commence transmissions,” the BBC said in a statement.

The BBC World Service produces uncensored news in 29 different languages. It is part-funded by the British government but editorially independent.

The Asia transmission station was moved to Thailand from Hong Kong in 1997 after the city was handed back to China.

The BBC did not give details of why the talks broke down.

But two sources said the network’s Thai-language service had become a sore point.

Sansern Kaewkumnerd, head of Thailand’s Public Relations Department, confirmed discussions had faltered and said it was “still unclear whether the contract would be extended or not extended”.