Margaret Thatcher had "laid the foundation of the successful relationship between Britain and China," former British foreign secretary Geoffrey Howe told Xinhua on Monday after the announcement of the former British prime minister's death.

"It is a sad moment for me," said Lord Howe, referring to Thatcher's death.

"She was fully engaged in foreign policy throughout her time as prime minister. She had to address a number of very different and important questions -- Hong Kong is one example," said Howe, who served under Prime Minister Thatcher at the time of negotiations about the return of Hong Kong to China in the 1980s.

"She was successful over Hong Kong. The achievement of a very stable future for Hong Kong was a success for both the Chinese leadership and for Margaret," he said.

"As history has shown Hong Kong has prospered," he said.

Negotiations began in the early 1980s between the British government, which administered Hong Kong as a colony, and the Chinese government over the territory's return to China.

A Sino-British Joint Declaration on the future of the territory was signed in 1984 that led to its return to China in 1997.

Lord Howe said, "I think Margaret laid the foundation for a successful relationship between the two countries. She is viewed as a very important figure in the management of British policy."

Howe said the Chinese leadership was keen to reach an effective settlement over Hong Kong, and so was Thatcher.

He said, "They did manage it very well on both sides, to make it a very effective and surviving relationship."

Lord Howe was a key member of Lady Thatcher's three governments between 1979 and 1990, serving as her finance minister, then as her foreign secretary, and then as her deputy.

His resignation from that post in 1990 and his resignation speech in the House of Commons were the key moments in a series of events which saw support fall away from her within her own party and which led to her resignation as prime minister to be replaced by John Major.

Lord Howe also touched on Lady Thatcher's influence on global superpower relations and on the direction of the European Union.

"East-West relations was a substantial issue, and the management of Britain's position in the European Union. She played a leading role in these issues," said Lord Howe.

A leading member of the right-wing of Lady Thatcher's party, David Davis MP, who entered parliament while she was still prime minister and who rose to be deputy leader of his party, was also saddened by her death.

Davis told Xinhua in a statement, "Millions of people in Britain and around the world owe her a debt of gratitude for their freedom and their quality of life, which was made possible by her courageous commitment to the principles of individual freedom and responsibility. Her passing is a very sad event and she will be greatly missed."

Lord Saatchi, who masterminded Lady Thatcher's publicity campaigns that were instrumental in her winning power in three successive general elections, told Xinhua in a statement, "Everyone wants to be immortal. Few are. Mrs Thatcher is. Why? Because her values are timeless, eternal."

He added, "Tap anyone on the shoulder anywhere in the world, and ask what Mrs Thatcher believed in, and they will tell you. They can give a clear answer to what she stood for."

"She developed all the winning arguments of our time -- free markets, low tax, a small state, independence, individuality, self-determination. The result was a revolution in economic policy and three election victories in a row," said Lord Saatchi.

Lady Thatcher founded the Center for Policy Studies (CPS), a leading London think-tank, in 1974 to propagate her political values.

The current director of the CPS told Xinhua, "Britain today faces great challenges, similar in many ways to the late 1970s -- in the economy, in the EU, the role of the state. We will advocate and promote policies based on her founding principles."