The 1888 Britain-Yorubaland Treaty was an international agreement concluded between States – ie Britain and the Yorubaland - in written form and governed by international law. The Treaty, which was negotiated for the Crown and signed on the Crown’s behalf on 23 July 1888, was ratified by the Crown on 16 June 1890. The Treaty, which was negotiated and signed in person by the Alaafin of Oyo on 23 July 1888, was ratified by him on acceptance of the consideration of £31.5s on 16 June 1890. Ratification meant that both Britain and the Yorubaland consented to be bound by the terms of the treaty.

It has been suggested that nevertheless, the 1888 Britain-Yorubaland Treaty could not be law because it had not been explicitly domesticated. The constitutional practice in Britain in 1888 was that the Crown, under the prerogative rights, had the sole power to negotiate and enter into a treaty, to determine its content as well as to ratify it. However, a treaty had no effect in law unless it had first been made part of domestic law, ie proved by Parliament.

This ‘British rule’ of treaties was described in some detail by Justice Iredell in Ware v. Hylton, 3 U.S. (3 Dall.) 256, 274-75:

‘[I]t is an invariable practice in that country, when the King makes any stipulation [in a treaty] of a legislative nature, that it is carried into effect by an act of Parliament. The Parliament is considered as bound, upon a principle of moral obligation, to preserve the public faith, pledged by the treaty, by passing such laws as its obligation requires; but until such laws are passed, the system of law, entitled to actual obedience, remains de facto, as before.’

However, although a treaty was not directly received into British domestic law, international law was part of the law of the land. Under international law, a treaty created rights and obligations that one nation owed to another independent of each other’s domestic laws. As a contract between nations, a treaty gave rise to binding obligations under international law. Even if a country could not enforce a treaty provision in its domestic courts because it was non self-executing, its provisions were still binding under international law. Britain thus had an international legal obligation to comply with the terms of the 1888 Britain-Yorubaland Treaty.

According to the Island of Palmas Case (BYBIL, Vol. 30 (1953) p. 1):

‘lt can now be regarded as an established principle of international law that in such cases the situation in question must be appraised, and the treaty interpreted, in the light of the rules of international law as they existed at the time, and not as they exist today.’

The 1888 Britain-Yorubaland Treaty came under the Foreign Jurisdiction Act 1843 (FJA). The FJA was concerned with the acquisition of power and jurisdiction in territories outside of the British sovereignty. The purpose of the FJA was to make clear the British law regarding power and jurisdiction that the Crown had acquired. The FJA was,

‘An Act to remove Doubts as to the Exercise of Power and Jurisdiction by Her Majesty within divers Countries and Places out of Her Majesty's Dominions, and to render the same more effectual.’

The Crown employed a variety of means to acquire power and jurisdiction outside of the British sovereignty:

‘'WHEREAS by Treaty, Capitulation, Grant, Usage, Sufferance, and other lawful Means Her Majesty hath Power and Jurisdiction within divers Countries and Places out of Her Majesty's Dominions: And whereas Doubts have arisen how far the Exercise of such Power and Jurisdiction is controlled by and dependent on the Laws and Customs of this Realm, and it is expedient that such Doubts should be removed:' Be it therefore enacted by the Queen's most Excellent Majesty, by and with the Advice and Consent of the Lords Spiritual and Temporal, and Commons, in this present Parliament assembled, and by the Authority of the same, That it is and shall be lawful for Her Majesty to hold, exercise, and enjoy any Power or Jurisdiction which Her Majesty now hath or may at any Time hereafter have within any Country or Place out of Her Majesty's Dominions, in the same and as ample a Manner as if Her Majesty had acquired such Power or Jurisdiction by the Cession or Conquest of Territory.’

In regard to treaties, Mr Curzon, Under Secretary of State for Foreign Affairs (Hansard 2 April 1897) said this:

‘The way the thing works in practice is as follows:—Foreign Powers make agreements with each other; agreements not necessarily binding on any but those who make them, and often not accepted by other Powers. They make these agreements as to spheres of influence, and within these spheres of influence they consider that their agents are at liberty to go about and make treaties.’

Cameroon v Nigeria Counter-Memorial of the Federal Republic of Nigeria Vol. I @para 6.26:

‘…it is clear…that the local Rulers in West Africa were generally regarded by the European powers as having rights and obligations in international law, including treaty-making powers and sovereignty over territory.’

Treaties were drawn up to create legal relationships. The European powers regarded treaties as the foundation upon which to build the colonial edifice. By virtue of Section II of the Act, any treaty made under the FJA, such as the 1888 Britain-Yorubaland Treaty, was self-executing and did not require additional parliamentary approval:

‘And be it enacted, That every Act, Matter, and Thing which may at any Time be done, in pursuance of any such Power or Jurisdiction of Her Majesty, in any Country or Place out of Her Majesty's Dominions, shall, in all Courts Ecclesiastical and Temporal and elsewhere within Her Majesty's Dominions, be and be deemed and adjudged to be, in all Cases and to all Intents and Purposes whatsoever, as valid and effectual as though the same had been done according to the local Law then in force within such Country or Place.’

The FJA did not exceed the power required by the Crown pursuant to treaties. Obligations relating to those treaties were to be observed regardless of municipal law. Britain thus could not justify failure to comply with treaty obligations imposed on it by the 1888 Britain-Yorubaland Treaty by reference to its municipal law.

According to the Greek and Bulgarian Communities Case (PCIJ Series B No 15 p26-7, 1930),

‘It is generally accepted principle of international law that in relations between powers who are contracting parties to a treaty, the provisions of municipal law cannot prevail over those of a treaty.’

A rule of the British law did not become extinct merely from disuse. The British government could not take action to remove rights guaranteed under a treaty that the Queen had ratified. The Queen ratified the 1888 Britain-Yorubaland Treaty on 16 June 1890.