BBC World Service staff warned that the plan to move the broadcaster's Chinese service headquarters from Britain to Hong Kong may threaten its editorial independence and integrity.
They also said the plan would put at risk the safety of BBC staff who have been critical of Beijing.
The staff warning came a day after the European Union released a report which said the principal actors in the "one country, two systems" electoral reform process were unable to reach a compromise and that no progress was made toward the goal of introducing universal suffrage for the election of the Chief Executive from 2017.
A letter from Britain's National Union of Journalists was sent to the former BBC chairman and the last Hong Kong governor Chris Patten, the Department for Culture, Media and Sport and the Foreign Office, urging the authorities "to intervene and ask the BBC to reconsider these ill-considered and unjustifiable plans."
In the letter obtained by The Standard, Howard Zhang of the union said: "Offshoring this service, chopping it at the roots and transplanting it to Hong Kong is incredibly short-sighted."
It also cited the sacking of the editor- in chief of the Chinese-language newspaper Ming Pao, the change in ownership of the South China Morning Post, and the case of the missing booksellers. Zhang said additional posts in Hong Kong, if not filled by existing staff, could go to newly appointed local employees who may not maintain an independent voice of authority in the region.
"Worryingly, nor will they have the security of a British passport to protect them from the potential wrath of the Beijing regime," he said.
According to The Guardian, the BBC World Service head of languages Liliane Landor said in an internal e-mail to director of news James Harding that the relocation is to enable the audience to be served in the right time zone.
"Competitors are outperforming us. In such an important market, we have had to look at what we are doing that's not working and try to address this," she said. "Therefore we propose to restructure the team, basing the majority of roles in Hong Kong, where they will be in the right time zone to serve the audience, and in the best place to produce more original and relevant content."
A BBC spokeswoman on Wednesday said the change in the Chinese service was to improve the broadcaster's reach and impact in China and stressed that editorial independence would not be threatened.
"In a fiercely competitive market, we need more first-hand reporting in China and cannot continue relying on content produced in London, nine hours behind the relevant time zone. We believe these changes will enable us to provide our Chinese audience globally with an independent and compelling news offer it can't find elsewhere. They will also help us to explore new ways to circumvent web blocking and censorship,'' she said.
"While safety is always of paramount importance, BBC Chinese staff are able to report from Hong Kong independently and without interference from authorities. We believe this will continue in Hong Kong which hosts regional headquarters and offices for more than 100 leading international media organizations.''
A Department for Culture, Media & Sport spokeswoman declined to comment when asked by The Standard, saying "the BBC is independent of the UK government in this regard."