Why did the East India company employ its own Army and Navy, separate from England

The company used its armed force to subdue Indian states and principalities with which it had initially entered into trading agreements, to enforce ruinous taxation, to carry out officially sanctioned looting, and to protect its economic exploitation of both skilled and unskilled Indian labor.

This was because it began with a rebellion by Indian troops (sepoys) serving in the army of the British East India Company. British rule in India was handled by the East India Company. ... The British preferred to think of the rebellion as a mutiny because this word disguised the huge scale of the rebellion.

Explanation:

might be agreeing to participate ethically with other european nations in the slave trade

or notifying other european nations when taking possession   of african territories