What is private international law? 

Private international law, also known as “conflict of laws”, is the set of rules governing cross-border legal disputes between private citizens or other private entities. It encompasses a broad range of topics including: which court has jurisdiction to hear a case; which country’s law should be used to determine a dispute (also known as applicable law), and whether judgments made in a foreign court can be recognised and enforced in a different jurisdiction. Private international law principles apply across the spectrum of civil law matters. This covers everything from international family disputes (such as child abduction or divorce proceedings) through to commercial matters such as cross-border contracts and international debt enforcement. 

Why is private international law important? 

Private international law aims to allow streamlined civil judicial cooperation across national borders. It seeks to avoid the need for multiple sets of court proceedings relating to the same dispute, particularly where there is a risk that these could result in conflicting judgments. All of the parties therefore save time and money by having their dispute resolved in a consistent and efficient manner, and this in turn improves access to cross-border justice for ordinary citizens. 

Where does private international law come from? 

Private international law derives from a mixture of domestic rules made by national authorities and international rules agreed between different states. These can come in the form of bilateral agreements between countries, or can take the shape of multilateral treaties which numerous nations have signed up to.  

These multilateral treaties aim to harmonise the application of private law across many different jurisdictions, and are developed and promoted by dedicated international organisations. Examples of such treaties include: 

  • The Hague Conventions (see below), which cover a vast range of topics from the international sale of goods through to taking evidence abroad, trusts, child support and access to justice. 
  • The Singapore Convention on Mediation, which sets out rules on the international recognition of mediated settlements and has 53 signatories including China, Russia and the United States. 
  • The Lugano Convention, an international treaty between the EU’s Member States and Iceland, Norway and Switzerland. The Convention covers matters of jurisdiction in cross-border civil and commercial disputes, as well as the international recognition and enforcement of judgments made in the signatory countries. The UK applied to join the Lugano Convention on 8 April 2020 and is currently awaiting the outcome of its application. 

Key institutions in private international law 

Some of the most important international organisations in the private international law sphere are as follows. 

The Hague Conference on Private International Law 

Formally established in 1955, the Hague Conference on Private International Law (HCCH) is an international inter-governmental organisation with 86 members (85 states and the EU). Its mission is to work towards the “progressive unification” of private international law regimes by establishing internationally agreed approaches on relevant issues, such as the recognition and enforcement of judgments or choice of court. The HCCH does this in an attempt to ensure that businesses and individuals can rely on legal security in spite of international differences between legal systems.  

The HCCH works by adopting international Conventions which members can sign up to and ratify in their own domestic legal systems. Non-members can also become parties to Hague Conventions, and even where countries choose not to sign, they can use the Conventions as a point of reference for an international standard of collaboration. In addition to the topics mentioned above, the most widely ratified Conventions deal with the abolition of legislation; service of process; international child abduction; intercountry adoption; conflict of laws on the form of testamentary dispositions; and recognition of divorces.   

Recent Conventions include the Hague Convention on Choice of Court Agreements (2005) and the Hague Convention on the Recognition and Enforcement of Foreign Judgments in Civil or Commercial Matters (2019). The HCCH is currently looking into the topics of cross-border mediation in family matters; choice of law in international contracts and access to the content of foreign law, and is considering the need for further Conventions in these areas. 

The United Nations Commission on International Trade Law (UNCITRAL) 

UNCITRAL is a United Nations legal body and focusses specifically on the field of commercial law reform and harmonising global rules on international business. It was established by the UN in 1966 and is made up of 60 UN member states elected by the UN General Assembly for a term of six years. UNCITRAL’s core aim is to remove and reduce legal obstacles to the smooth flow of international trade, simplifying transactions and reducing the associated costs for businesses. It uses a variety of instruments to achieve this aim, including conventions, model laws, legislative guides, and contractual rules that can be incorporated into commercial contracts and legal guides. Key topics covered by its activities include: 

  • sale of goods (e.g. the United Nations Convention on Contracts for the International Sale of Goods (Vienna, 1980) and the UNCITRAL Legal Guide on International Countertrade Transactions (1992)); 
  • transport of goods (e.g. the United Nations Convention on the Carriage of Goods by Sea (Hamburg, 1978)); and 
  • dispute resolution (e.g. the UNCITRAL Arbitration Rules (1976) and the UNCITRAL Model Law on International Commercial Conciliation (2002)). 

The Institute for the Unification of Private Law (UNIDROIT)

Established in 1940, UNIDROIT is an independent intergovernmental organisation focussed on harmonizing private and commercial law between nations. It has 63 member states, and like the other institutions set out above, it works through a mixture of conventions, model laws, principles and legal and contractual guides. Its activities cover a range of spheres, including capital markets (e.g. the Geneva Convention on Substantive Rules for Intermediated Securities); civil procedure (e.g. the American Law Institute/UNIDROIT Principles of Transnational Civil Procedure (2006)) and cultural property (e.g. the UNIDROIT Convention on Stolen or Illegally Exported Cultural objects (1995)). It also has work in progress in a number of other legal areas, including digital assets, bank insolvency and enforcement best practice.