LONDON, JUNE 26 -- Fang Lizhi, China's most prominent dissident, said today he will continue to work for progress in his homeland as he prepares to start an academic life in Britain.

Fang and his wife, Li Shuxian, arrived in London late Monday after Chinese authorities allowed them to leave their yearlong refuge in the U.S. Embassy in Beijing. The couple, charged with "counterrevolutionary" activity, had been in the embassy since shortly after the June 3-4, 1989, military crackdown on democracy protesters in Beijing.

"As citizens of China, we hope to do whatever we can in the future to help China's continuing progress and development," Fang said in a statement issued through the Royal Society in London. He did not meet with journalists.

The society, a prestigious scientific organization, invited the astrophysicist to Britain. Fang, 54, will be a senior visiting fellow at Cambridge University's Institute of Astronomy.

A British Foreign Office spokesman said Fang was allowed to leave China after a "tripartite agreement" among Britain, China and the United States. The Foreign Office refused to elaborate on negotiations among the three countries.

{Britain said today it had not imposed any condition of political silence on Fang in agreeing to grant him a renewable six-month visa, the Reuter news agency reported. "He has entire freedom of speech," a Foreign Office spokesman said.

{Reuter also reported that Desaix Anderson, deputy assistant secretary of state, arrived in Beijing for five days of talks with Chinese officials. He is the most senior U.S. official to visit China since National Security Adviser Brent Scowcroft made a trip there last December.}

Fang's statement said he and his wife were looking forward to a few days of quiet to "rest and recuperate, and to have some medical tests." U.S. media reports said Fang recently suffered a mild heart attack but refused to be treated in a Chinese hospital.

"The past year has been difficult for us, but we have received strong support from the international scientific community and friends everywhere," the statement said.

Fang and Li, a physicist, have two sons. Fang Ke is a student at Wayne State University in Detroit and the other, Fang Zhe, is a student at Beijing University.

"We understand that our son in China will soon be able to study abroad, and we are naturally looking forward to a family reunion," Fang said in the statement.