Britain intervened in the Lagos kingship energy wrestle by bombarding Lagos in 1851, deposing the slave-trade-friendly Oba Kosoko, helping to put in the amenable Oba Akitoye and signing the Treaty among Great Britain and Lagos on 1 January 1852. Britain annexed Lagos as a crown colony in August 1861 with the Lagos Treaty of Cession. By the middle of the 20th century, a fantastic wave for independence was sweeping across Africa.