A confluence of interests in Lagos from the now deposed Akitoye, who had allied himself with the anti-slavery cause in order to get British support, the Anglican missionaries in Badagry who were in contact with Akitoye, and Egba and European traders who want freer movement of goods, has ratcheted up British intervention in Lagos.

Akitoye's anti-slavery position appears born of self-interest, considering his connection with the well known slave trader Domingo Martinez, who had backed Akitoyes's unsuccessful attack on Lagos in 1846.

In November 1851 a British party met with Oba Kosoko, Akitoyes's successor, to present a proposal of British friendly relations along with giving up the Trans-Atlantic Slave Trade.

The proposal is rejected by Kosoko "on the technical reason that Lagos was under the Oba of Benin and that it was only that Oba who could deal with foreign powers concerning the status of Lagos." (Onabamiro, Sanya. Glimpses Into Nigerian History: Historical Essays. Macmillan Nigeria, 1983. p. 43.)

British Consul John Beecroft, following Kosoko's successful repulsion and defeat of British forces, writes to the Oba of Benin on December 4, 1851, declaring that "Kosoko, by opening fire on a flag of truce, had declared war on England" and therefore had to be replaced by Akitoye.

He threatens that Kosoko has until the end of the month to surrender otherwise "Lagos would be totally destroyed by fire". 

On December 26, 1851, in what is now known as the Bombardment of Lagos or Reduction of Lagos, HMS Bloodhound, HMS Teazer, and a flotilla of boats mount an attack on the Oba's palace.

Kosoko puts up a spirited defense but by December 28 the battle known locally as Ogun Ahoyaya or Ogun Agidingbi (after boiling cannons) is over, with Kosoko and his followers fleeing to Ijebu.

Akitoye is now re-installed as Oba of Lagos with British support.

On January 1, 1852 Akitoye will sign a treaty between Great Britain and Lagos abolishing the slave trade.

Lagos, where the British will concentrate activities after 1851, had been founded as a colony of Benin in about 1700.

A long dynastic struggle, which has become entwined with the struggle against the slave trade, results in the overthrow of the reigning oba and the renunciation of a treaty with Britain to curtail the slave trade.

Britain is determined to halt the traffic in slaves fed by the Yoruba wars and responds to this frustration by annexing the port of Lagos in 1861.

Hereafter, Britain will gradually extend its control along the coast.

The signing of the 1852 Treaty between Great Britain and Lagos abolishing slavery ushers in the Consular Period in Lagos' history, wherein Britain provides military protection to Lagos.

The British Empire establishes bases in Lagos in 1861 to stop the slave trade.

British Prime Minister Lord Palmerston notes in 1861, "the expediency of losing no time in assuming the formal Protectorate of Lagos" following threats from Kosoko and the French, who are positioned at Wydah.

William McCoskry, the Acting Consul in Lagos, with Commander Bedingfield, had convened a meeting with Oba Dosunmu on July 30, 1861, aboard HMS Prometheus, where Britain's intent was explained and a response to the terms were required by August 1861.

Dosunmu had resisted the terms of the treaty but under the threat to unleash violence on Lagos by Commander Bedingfield, Dosunmu relents and signs the Lagos Treaty of Cession on August 6, 1861.

The United Kingdom annexes Lagos Island, in modern-day Nigeria, on January 1, 1862.

British expansion accelerates in the last decades of the nineteenth century.

The early history of Lagos Colony is one of repeated attempts to end the Yoruba wars.

In the face of threats to the divided Yoruba states from Dahomey and the Sokoto Caliphate, as represented by the emirate of Ilorin, the British governor—assisted by the CMS—succeeds in imposing peace settlements on the interior.

British intervention in the region of present Nigeria becomes more insistent in the 1870s and 1880s as a result of pressure from missionaries and liberated slaves returning from Sierra Leone.

There is also the necessity of protecting commerce disrupted by the fighting.

The method of dealing with these problems is to dictate treaties that inevitably lead to further annexations.

Colonial Lagos is a busy, cosmopolitan port, reflecting Victorian and distinctively Brazilian architecture and the varied backgrounds of a black elite, composed of English-speakers from Sierra Leone and of emancipated slaves repatriated from Brazil and Cuba.

Its residents are employed in official capacities and are active in business.

Africans also are represented on the Lagos Legislative Council, a largely appointed assembly.