What was the outcome of the Nanjing Treaty for the British?

The Treaty of Nanjing was signed in 1842.  It was the
result of the first Opium War.  It was the first of what are known as the "Unequal
Treaties" because of the fact that the treaties forced concessions from China without
giving anything in return.

In the Treaty of Nanjing, the
British mainly got things that they wanted for trade purposes. Before the treaty,
British merchants could trade only with specified people in one city (Canton).  The
treaty abolished that system and allowed the British to trade with whoever they wished
in Canton and in four other ports.

The other major outcome
of the treaty was that Britain took possession of Hong Kong.  This gave the British a
secure base of operations in China.  It allowed them to have an area from which to trade
that was completely under their jurisdiction.