Political reporter Robert Hutton of Bloomberg, whose website is blocked in China, told not to attend event

Downing Street has protested to the Chinese authorities about a "completely inappropriate" decision to bar a British journalist from a press conference in Beijing with David Cameron and his Chinese counterpart, Li Keqiang.

No 10 raised "deep concerns" on two occasions with Chinese officials after the foreign ministry excluded Robert Hutton, a political journalist with the US wire service Bloomberg, from the event at the Great Hall of the People on Monday.

British officials in Beijing informed Hutton, a member of the British parliamentary lobby who is accompanying the prime minister to China, that he would not be admitted to the press conference.

Hutton was informed of the decision by an official on a bus ride from Beijing airport after the prime minister's overnight flight from London. The official said: "We have been told by the Chinese authorities that it would not be appropriate for you to attend."

The Bloomberg website is blocked in China after it ran stories about the wealth of families of senior leaders, including relatives of the president, Xi Jinping. Bloomberg last month denied killing a similar sensitive story after a New York Times report that said editors had been concerned its ability to report from China would be compromised if it ran the piece. Bloomberg said the article was still in preparation.

A No 10 spokesman said: "As soon as this issue became apparent on Sunday, we raised our concerns at senior levels and made clear it would be completely inappropriate to exclude journalists from the press statements. When we heard what had happened today we expressed our deep concern to senior Chinese officials about journalists being blocked."

The two leaders each read out a lengthy statement and declined to answer questions at the press conference, which ended with applause.

The decision by Chinese officials to bar a journalist from a press conference – technically called a press statement because no questions were permitted – highlights the challenge of improving trade ties with China. Cameron, whose relations with Beijing became strained after he met the Dalai Lama last year, arrived in Beijing pledging to lead a "dialogue of mutual respect and understanding" which would see him acting as China's strongest advocate in the west.

The strong reaction by No 10 shows that it is prepared on occasions to draw a line with the Chinese.