The Suez Canal, which linked the Mediterranean Sea to the Red Sea, meaning that British ships did not have to sail around Africa to reach India, a hugely important route for British (and French...
The empire got trade goods like spice, herbs, fabrics, rice, teaBigger and better empireOpium was a huge export from India, especially into China which created huge revenue for the British Empire.
Land, Tax, more knowledge taken from the people of Singapore [if they have some that the British did not], more CHEAP Labour, more resources...etc. etc.