Lagos Colony was a British colonial possession centred on the port of Lagos in what is now southern Nigeria. Lagos was annexed on 6 August 1861 under the threat of force by Commander Beddingfield of HMS Prometheus who was accompanied by the Acting British Consul, William McCoskry. Oba Dosunmu of Lagos (spelled "Docemo '' in British documents) resisted the cession for 11 days while facing the threat of violence on Lagos and its people, but capitulated and signed the Lagos Treaty of Cession. Lagos was declared a colony on 5 March 1862. By 1872 Lagos was a cosmopolitan trading center with a population over 60,000. In the aftermath of prolonged wars between the mainland Yoruba states, the colony established a protectorate over most of Yorubaland between 1890 and 1897. The colony and protectorate were incorporated into Southern Nigeria in February 1906, and Lagos became the capital of the protectorate of Nigeria in January 1914. Since then, Lagos has grown to become the largest city in West Africa, with an estimated metropolitan population of over 9,000,000 as of 2011.
when did lagos become a colony of britain
5 March 1862