London — The British lion is trying anew to persuade the Chinese dragon to let it keep its shop window on the Chinese mainland - Hong Kong.
This is part of a major British drive to boost trade in Asia. Britain is also aiming for bigger exports to, and imports from, the enormous markets of China and Japan. But it will find the going rough as it struggles to modernize its own economy at home.
The issue of Hong Kong, Britain's last Asian colony, is high on the agenda as Prime Minister Margaret Thatcher prepares for her first formal visit to Peking later this month. Her journey Sept. 16-29 also will take her to Japan, Hong Kong itself, and India.
The Thatcher trip will carry strategic and diplomatic implications, and some anti-Soviet overtones. British prime ministers abroad these days tend to be traveling salesmen and economic ambassadors. Mrs. Thatcher is no exception.
Inevitably almost the entire visit will carry an economic aspect. Mrs. Thatcher's message to Deng Xiaoping and Premier Zhao Ziyang in China, and to Prime Minister Zenko Suzuki in Tokyo, will be that British inflation has fallen and its workers show less inclination to strike.
British industry, she will say, is slowly shifting to modern, more efficient forms, especially in energy, telecommunications, and transport.
She also travels with the aura of the leader who took on and beat Argentina to regain possession of the Falkland Islands. Mrs. Thatcher believes that the world standing, not only of herself but also of Britain, has been boosted as a result. Whether she is right, and how much emphasis China and Japan attach to the Falklands episode, remains to be seen.
While Britain has only 4.5 percent of Hong Kong's trade, the Crown Colony is of almost inestimable value to Britain and other countries as a display window for sales to China, Japan, and the rest of Asia, and as a center of banking, air travel, shipping, and commerce.
Hong Kong is the third largest container port in the world; in 1979 it was the world's largest exporter of clothing. Britain exports around (STR)440 million ($748 million) worth of goods to Hong Kong and earns (STR)200 million more in ''invisibles.''
China does not recognize the imperial treaties that granted Britain Victoria Island and Kowloon in perpetuity in the last century, nor the leases that gave London the New Territories for 99 years until 1997.
With normal 15-year loan and mortgage leases now being signed expiring in 1997, this is an important year for the colony. It needs reassurance that stability will continue.
Officials here say Mrs. Thatcher will not solve the issue when she sees Messrs. Deng and Zhao between Sept. 22 and 26, but hopes to ''maintain the dialogue.'' It is expected that she will try for a statement that will at least partly reassure the colony's 5 million people.
Officials expect that China, which generates 35 to 40 percent of its foreign earnings through Hong Kong, will want to keep its own window on the West.
Uncertain as yet is whether it will tacitly agree to the current British status, or insist on a lease-back or other arrangement. One possibility is that China will take back sovereignty but grant Hong Kong special economic status.
In Japan, Mrs. Thatcher will urge the Japanese to buy more British goods and establish more Japanese manufacturing of various kinds in Britain.
In Japan, Mrs. Thatcher will try to persaude the Nissan Company to establish a large Datsun plant in Britain. The company shelved plans to do so earlier this year.
She will urge the Japanese to buy more British goods, and establish more Japanese manufacturing plants of various kinds in Britain.