Why was slavery brought to the british colonies

Well, slavery, amongst European colonial powers, came into being because of the establishment of settlements and colonies in the New World/Americas. The sicknesses & illnesses the Europeans brought to the Americas nearly wiped out the native residents, leaving little to no indigenous populous. Also, the natural friction between the locals and colonisers would've resulted in an obvious lack of cooperation and colonisers were never sent over in huge numbers, resulting in limited manpower. So, slavery was a way of providing a cheap labour & workforce in the new territories without having to resettle entire European populations. The colonisers ran the colonies and established settlements while the slaves effectively built them and their economies.

Spanish conquistadors demanded labour from natives.