In accordance with the provisions of the withdrawal agreement (Article 171), an arbitration body is established to resolve disputes over the interpretation and application of the provisions of the agreement between the parties. Arbitration committee members are appointed for any dispute in the areas listed on a list of arbitrators to be established by the Joint Committee of the Withdrawal Agreement. If it is the law applicable to the dispute, nothing will change, even if the transitional provisions of the withdrawal agreement do not apply. The United Kingdom has adopted legislation to incorporate Rome I and Rome II into English law, in accordance with the law applicable to contractual and non-contractual obligations (modification, etc.). (withdrawal from the EU) Regulations 2019 (which come into force at the end of the transition period instead of the original withdrawal date) and the English court will therefore apply the same rules as currently to determine the applicable law. Of course, the EU courts will continue to apply Rome I and Rome II, so that a choice of English law is effective to the same extent as it is now, and Brexit will not affect the rules applied by arbitration tribunals and arbitration tribunals in non-EU countries. Given the many references to EU law, it is likely that a dispute in the context of the withdrawal agreement will raise questions about the proper interpretation and application of EU law. For example, if the UK adopts a subsidy programme including business assistance in Northern Ireland, the problem would be that these measures would comply with EU state aid rules, as interpreted by the ECJ. However, the need for a reference may be less likely if the current disagreement over the UK domestic market law were referred to an arbitration tribunal. The language of Article 174, paragraph 1 of the withdrawal agreement follows the language of Article 267 of the Treaty on the Functioning of the European Union (hereafter the TFUE). Under Article 267 of the TFUE, courts of last instance are required to produce documents, unless «the correct application of EU law is sufficiently obvious to leave no reasonable margin of doubt» (C-416/17). In view of the comparable texts of Article 267 of the EUTF and Article 174, paragraph 1 of the withdrawal agreement, an arbitral tribunal may consider that there is no indication whether one of the parties publicly acknowledges a breach of the withdrawal agreement and that the proper application of EU law leaves no room for reasonable doubts in the present circumstances. In the United Kingdom, existing EU legislation at the end of the transition period will continue to be regarded as a maintained EU right until a decision is taken on its amendment or repeal.
With regard to the interpretation of this maintained Community law, the European Union Act (The Withdrawal Act 2018) provided in its original legal order that courts below those of the Supreme Court would apply the EU jurisprudence in force before the withdrawal; The Supreme Court would not be bound, but would have to apply the same test it would apply in deciding to deviate from its own jurisprudence.