Members of a pro-government group gather outside the Foreign Correspondents' Club in Hong Kong to protest a scheduled talk by pro-independence advocate Andy Chan Ho-tin.

Hong Kong has long profited on its unique position as a culturally Chinese city with freedom of expression, rule of law and an incorruptible civil service.

Those attributes turned it into a remarkable success as a dynamic banking and trade center known worldwide for being a safe, efficient and reliable place to do business. But an unprecedented decision by local immigration authorities to effectively expel a Hong Kong-based foreign journalist for a prestigious British newspaper has thrown that equation into question.

Authorities' rejection of a new work visa for Victor Mallet, an editor with the Financial Times, "sends a worrying signal" for Hong Kong, Tara Joseph, the president of the local American Chamber of Commerce, said in a Monday statement.

"Without a free press, capital markets cannot properly function, and business and trade cannot be reliably conducted," added Joseph, a former president of the Foreign Correspondents' Club of Hong Kong.

On Friday, the Financial Times announced that Mallet's request for a renewal of his visa had been rejected. The FT said no reason was given and Hong Kong immigration authorities said the same day they would not comment on individual cases.

Such applications have traditionally been approved as a matter of course in Hong Kong. The situation is different in neighboring China, where authorities have used actual and threatened expulsions of journalists as punishment for reporting they find sensitive or embarrassing.

Hong Kong, a former British colony, was famously promised it would have a high degree of autonomy and its legal system would not change for 50 years when it became a special administrative region of China in 1997 under the "one country, two systems" formula, but the situation has been seen as steadily eroding for a number of years.

Chief Executive Carrie Lam, Hong Kong's top official, was pressed by journalists Tuesday on Mallet's case, but refused to comment on specifics.

"I can assure you ... freedom of expression, freedom of reporting are core values in Hong Kong," she said, according to an official press release, adding that she and the government would protect such rights.