Why did the british participate in the crimean war?

The Crimean War (1853-1856) was a major European conflict fought by the coalition of Britain, France, Turkey and Sardinia against Russia, mainly on the Crimean Peninsula, for rule in the Middle East. One of the main reasons why the British participated was that they were fearful of Russia’s domination of the Black Sea and expansion in the Middle East, especially to the area of British India. Eventually the Russians were defeated when the city of Sevastopol fell on allied hands on September 9, 1855; the signing of the Treaty of Paris on March 30, 1856, formally marked the end of the Crimean War.

answer; i believe the two groups were irish immigrants and chinese immigrants;