Because Britain had a 99 year lease on the New Territories of Hong Kong, and this was due to be returned to the Chinese by 1997. The UK didn't have to handover Hong Kong island, but if it didn't then it would have lost too many facilities such as places of work and airports to China for it to function as its own city, and so it was handed back on the condition that it would be a democracy for 50 years.
The British did not "sell" Hong Kong. They were merely re-transferring sovereignty back to the People's Republic of China.
Under the Treaty of Nanking, Hong Kong was ceded to the British Empire under a 99-year lease. The lease terminated in 1997, which was when the British returned Hong Kong to Chinese authority.
The entire territory of Hong Kong was never given to Britain as the form of its boundaries today. After Britain defeated the Qing Dynasty of China in the First Opium War, China ceded Hong Kong Island to Britain permanently. Kowloon and Stonecutter's Island were also later given to Britain permanently after it won the Second Opium War. With Hong Kong's growing population and economy in the 1890s, Britain decided to lease a part of China's territory and Chinese islands surrounding Hong Kong Island and Kowloon for 99 years in 1898 to make room for development. As the lease's deadline approached, in 1984 Britain and China began discussing the future of Hong Kong and giving China back Hong Kong. Technically, only the New Territories and outlying islands were supposed to be given back. However, the connection of the leased land and the areas ceded to Britain permanently had been too intertwined to separate both economically and socially. China rejected Britain's plan of joint rule of colony as well as joint rule of Kowloon and Hong Kong Island while returning the leased land. In the end, both nations agreed on Britain leaving Hong Kong on July 1, 1997 while China was to allow Hong Kong to maintain its capitalist economy and semi-democratic government for at least 50 years after the handover.
Their 99 yr lease was up which is why they gave it back.
Prior to 1997, Hong Kong was a British territory.
It is Hong Kong
United Kingdom in 1997
Hong Kong is not a capital of any country. It is part of China.
The United Kingdom
The transfer of sovereignty of Hong Kong from the United Kingdom to the People's Republic of China occurred on July 1, 1997 at the Hong Kong Convention and Exhibition Centre in Wan Chai, Hong Kong.
On the 1st July 1997, the sovereignty of Hong Kong was transferred from the United Kingdom to the People's Republic of China.
After defeating China in a war, the United Kingdom (Great Britain) demanded China give up Hong Kong as part of the Treaty of Nanking
The transfer of sovereignity over Hong Kong from the United Kingdom to the People's Republic of China.
United Kingdom
Not until 1997. From 1841 to 1997 it was a Colony of the United Kingdom.
It was part of the United Kingdom (but not "England") when China loaned it to England in 1887. But then it was returned in 1997. So now, it is not a part of England. It is a part of China. No, Hong Kong is situated on China's south coast.