Identify the theories which describe the relationship between international law and domestic law and evaluate their relevance in UK law.

“In practice the differences between international law and a particular municipal system are minimised and every effort is made to achieve a harmonisation between the two systems”. The case of Salomon v Commissioners of Customs and Excise sets out that there is a prima facie presumption in UK law that parliament does not intend to act in breach of international law but by its very nature a presumption is rebuttable.

Modern theories or principles regarding the relationship between international and domestic law were developed in 1988 by a group of mainly commonwealth lawyers and are known as the ‘Bangalore Principles’. These principles provide that international law is not, as such, part of domestic law in most common law countries, that such law does not become part of domestic law until Parliament authorises by way of statute or judicial precedent etc, that the judges will not automatically incorporate areas of international law automatically and that where an issue of uncertainty arises in the domestic common law, the judge may seek guidance from an existing principle of international law. An example of this can be seen in the case of Derbyshire County Council v Times Newspapers Limited where Article 10 of the European Convention on Human Rights was referred to in order to ‘fill a gap’ in domestic law even though it had not been fully incorporated into UK law.

In terms of the relevance of the above theories to UK domestic law it is quite apparent that it is not a case of choosing one theory best suited to the relationship between international law and UK domestic law but to look at the different forms of international law and see what approach is taken, firstly, when dealing with domestic law on the international stage. It is apparent that international law is supreme, in that any provisions of domestic law pale in to insignificance and are therefore not recognised when it comes to complying with international law in front of an international tribunal as illustrated by the case of Alabama Claims Arbitration. This is also provided for via the provisions of Article 13 of the Draft Declaration on Rights and Duties of States 1949, which says that a state cannot use a provision of domestic law as a defence for not carrying out an obligation under international law.

It is now pertinent to look at how international law is dealt with before domestic courts in the UK in order to ascertain what status, and in a sense ‘weight’, international law carries within the UK. Due to the fact that the United Kingdom does not have a formal written constitutional document, it is necessary to look elsewhere in order to establish what relationship exists. In terms of customary international law, Wallace contends that the UK adopts a monistic approach and the case of West Rand Central Gold Mining Co. is said to provide a good illustration as to the position in the UK regarding the relationship of customary international law with UK domestic law. This case provides the authority that what is regarded to be customary international law will be applied by the domestic courts when an appropriate occasion arises. It would be foolish not to ask the question ‘what constitutes customary international law?’ There are certain principles or doctrines that are established and renowned for being customary international law but there is no international legislature or court that can declare something as being customary international law and so how do countries such as the Netherlands, who adopt a purely monistic approach, actually know what their law is? An example of the UK’s monistic approach to international law can be found in the case of Trendtex Trading Corporation v Central Bank of Nigeria in which Lord Denning said that if a court is satisfied that a rule of international law on a subject has changed over a period of time then the court can give effect to that change without waiting for the House of Lords to do so. In my view this provides a clear example of a monistic approach on the basis that customary international law can be treated as being part of the domestic law of the UK automatically – without the need for legislation or a ruling from the court of last instance.

There is however an exception to the assertion that as far as customary international law and UK domestic law are concerned the relationship is of a monistic nature and that is where the rule of customary international law is inconsistent with the domestic law. This point is illustrated by the case of Mortensen v Peters in which an appeal against a conviction on the basis that it contravened customary international law was thrown out, with the court citing the reason for this as being that it was not for the court to rule if an Act of parliament which had been passed by the House of Lords, the House of Commons and assented to by the King, was outwith their powers on the basis that the Act contravened customary international law. The court in that case also acknowledged the presumption that parliament did not intend to infringe international law when they passed an Act of Parliament but by its very nature a presumption may be rebutted and where there is a conflict between customary international law and domestic law before a domestic court, domestic law is supreme and any sanctions resulting from the infringement of international law are outwith the jurisdiction of the domestic courts.

Customary international law is not the only form of international law; another very important manifestation of international law is that of the treaty – a formal agreement between states. International law in the form of a treaty does not automatically become part of UK domestic law even if it has been signed but the government, which illustrates a somewhat dualistic approach when considering the relationship between international treaty law and domestic law. In order for a treaty to become incorporated into domestic law an enabling act is required. The main reason for this is due to the fact that the treaty making powers of the UK rest with the UK government, in the form of the Royal Prerogative, who can sign up to a treaty on their own, i.e. without the consent of a majority of the elected members of parliament and so the requirement of an enabling act, be it an Act of Parliament or a judicial decision, is a safety net so as to counteract the threat of an abuse of power or position by the government who could otherwise make laws ‘through the back door’ as it were. Another way of looking at the scenario is that the citizens of the state, who would be subject to the terms or a treaty, would not have a say in its enactment unless an Act of Parliament is passed and for an Act of Parliament to be passed the will of the citizens is expressed through the Members of Parliament they have elected. In the case of the enacting a treaty through the courts, this would be done by the judiciary who are independent from the government.

It is however the case that where a treaty has not yet been incorporated into domestic law, it can be used as guidance where domestic law is silent or ambiguous as was seen in the above case of Derbyshire County Council v Times Newspapers Limited and also in the case of Bhajan Singh where Lord Denning stated that the European Convention on Human Rights could be taken into when interpreting a statute which affects the rights and liberties of an individual. It is important to note that the European Convention on Human Rights has now been incorporated into UK domestic law by the Human Rights Act 1998 but at the time the above cases were heard the UK government had signed up to it but an enabling act had not been passed.

Having established the two main schools of thought as well as considering the Fitzmaurice compromise and to a certain extent the Bangalore principles, it is apparent that the relationship between international law and UK domestic law does not follow exactly either the monistic or dualistic school of thought. Where the relationship with customary international law can be said to be of a monistic nature, there is a contrast, in that the relationship between international treaty law and UK domestic law can be thought of as being of a dualistic nature and so it is safe to say that the relationship between the laws cannot be totally monistic or dualistic although there are visual traits of both schools of thought being present when dealing with different areas of international law and its relationship with UK domestic law. It therefore may be the case that an alternate theory, such as the Fitzmaurice compromise, may be best suited as a model for describing the relationship.

Word Count:                2025

Bibliography:

A Modern Introduction to International Law 7th Edition, Michael Akehurst, Routledge, 1997;

Cases and Materials on International Law 3rd Edition, Martin Dixon and Robert McCorquodale, Blackstone Press, London, 2000;

International Law Third Edition, Rebecca M. M. Wallace, Sweet & Maxwell, London, 1997.

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