During his time in Beijing, Cameron oversaw the signing of agreements in areas including space exploration and football training, and voiced support for a deal to free up trade between China and the European Union, China's largest trading partner. Such a deal could be worth up to 1.8 billion British pounds ($2.95 billion) a year to the British economy, the U.K. government says.

The Global Times also took Cameron to task for comments backing expanded democracy in former British colony Hong Kong, and said Britain is colluding with France and Germany to provoke China over the Dalai Lama. Cameron's visit was originally scheduled for last year, but was postponed by China after he met with the exiled Tibetan spiritual leader, who is reviled by Beijing.

"We've discovered that Britain is easily replaceable in China's European foreign policy," said the editorial in the newspaper's Chinese edition. "Moreover, Britain is no longer any kind of 'big country,' but merely a country of old Europe suitable for tourism and overseas study, with a few decent football teams."

China would respond in kind to all perceived diplomatic slights, the editorial said, adding that "in conclusion, we wish Prime Minister Cameron and his delegation a pleasant visit to China."

The editorial's sneering tone was typical of the strain of belligerent nationalism identified with the newspaper, published by the ruling Communist Party's official People's Daily. A similar editorial in the newspaper's English edition called Britain "just an old European country apt for travel and study."

Following talks with Chinese Premier Li Keqiang and President Xi Jinping, Cameron flew to Shanghai on Monday night for further meetings and to speak at a university. His trip is to conclude Wednesday in the southwestern city of Chengdu.

The trade deals signed had been in the works for months or years, and British business and Cameron's government had been anxious to finalize them. That was partly because of concerns that Britain was being less active in courting business with the world's second largest economy than rivals France and Germany.

Cameron's schedule underwent a number of last-minute changes and an expected news conference in Beijing was scrapped.

There were few signs of lingering political tensions, although Cameron's staff protested the exclusion from an event Monday at the Great Hall of the People of a British reporter for the U.S. financial news agency Bloomberg, which has fallen afoul of Beijing over some of its reporting.

Chinese Foreign Ministry spokesman Hong Lei said the reporter, Rob Hutton, had been excluded in order to give priority to journalists from China and Britain.