Who colonized Sierra Leone?

Who was the colonizers Prime Minister/President at that time?

Sierra Leone was colonized by the British in the late 18th century. At the time of colonization, the British Prime Minister was William Pitt the Younger, and the British monarch was King George III.

British prime Minister at the time when Sierra Leone got independence?

Sierra Leone gained independence from British colonial rule on April 27, 1961. At that time, the British Prime Minister was Harold Macmillan.

Who was the Nationalist leader of Sierra Leone and what was the political party called

The nationalist leader of Sierra Leone was Sir Milton Margai, and the political party he founded and led was called the Sierra Leone People's Party (SLPP).