<P> Colonial Nigeria was the area of West Africa that later evolved into the modern day Nigeria , during the time of British rule in the 19th and 20th centuries . British influence in the region began with the prohibition of slave trade to British subjects in 1807 . Britain annexed Lagos in 1861 and established the Oil River Protectorate in 1884 . British influence in the Niger area increased gradually over the 19th century , but Britain did not effectively occupy the area until 1885 . Other European powers acknowledged Britain 's power over the area in the 1885 Berlin Conference . </P>
who colonized nigeria and when did they do it
British rule in the 19th and 20th centuries