In the early 1980s talks began between Britain and China over the future of Hong Kong. The negotiations resulted in a promise of 'One country, two systems' when the territory changed hands in 1997. Hear from one of the British diplomats involved, Sir Anthony Galsworthy.

Photo: Margaret Thatcher and the Chinese Premier Zhao Ziyang exchanging copies of the Hong Kong Handover agreement in 1984. Credit Associated Press.