sigh... the history understander has logged on again
Nope, Hong Kong Island was already ceded to the UK decades earlier in 1842 and as I already pointed out to you the 99-year lease was for the new territories:
On June 9, 1898, the British under Queen Victoria brokered a 99-year lease agreement for the use of Hong Kong after China lost a series of wars fought over the British trade in tea and opium.[...]
Not naff but basic history
Nope, Hong Kong Island was already ceded to the UK decades earlier in 1842 and as I already pointed out to you the 99-year lease was for the new territories:
British Hong Kong - Wikipedia
en.wikipedia.org
The island was ceded to Britain by the Treaty of Nanking, ratified by the Daoguang Emperor in the aftermath of the war of 1842. It was established as a crown colony in 1843. In 1860, the British took the opportunity to expand the colony with the addition of the Kowloon Peninsula after the Second Opium War, while the Qing was embroiled in handling the Taiping Rebellion. With the Qing further weakened after the First Sino-Japanese War, Hong Kong's territory was further extended in 1898 when the British obtained a 99-year lease of the New Territories.