As parties assess changes in the legal, economic and regulatory landscape caused by the exit, and the costs and other implications on their contractual relationships, they are more likely to consider the scope for avoiding contractual obligations, such as seeking to rely on a force majeure clause or a material adverse change clause, or arguing that a contract is frustrated.
If there is a Referendum, businesses would wish to consider carefully the contractual mechanisms on which they (or their counter-parties) may seek to rely to avoid contractual obligations in the context of any negotiation about contractual performance in the event of a UK exit.
A time of upheaval and changes in the regulatory or legal system may also provide scope for claims against the UK by investors under its bilateral and multi-lateral investment treaties, based for example, on their expectations as to the stability of the regulatory system into which they invested.
The fact that there may be uncertainty as to the content of some aspects of English law after a withdrawal could in itself lead to disputes, as parties seek to test the position. This could arise, for example, from the potential for UK legislation to be repealed or amended to the extent that it is no longer required to comply with an EU Directive. In addition, there may be scope for argument regarding the extent to which principles established by EU case law prior to the exit should continue to influence the UK courts' interpretation of UK law, for example, where UK legislation introduced post-exit is similar to an EU Regulation.
With regard to dispute resolution procedures, an exit from the EU would mean that key EU legislation regarding jurisdiction and reciprocal enforcement of judgments (namely the Brussels Regulation) would no longer apply to the UK. It is likely that the UK would seek to reach an agreement with the EU on such matters, reflecting similar arrangements to those now in place. In default of that, English law has its own domestic rules on jurisdiction and enforcement of judgments which would very likely apply in international cases in the English courts involving EU parties. Importantly such rules will respect any choice of court provision, and so in commercial cases where a choice has been exercised there is unlikely to be any material effect on the conduct of cases.
At the enforcement stage, the enforcement of English judgments abroad, or of EU judgments in England, would be more cumbersome, and would rely on domestic rules of law in the relevant jurisdiction. In the absence of a fresh agreement with the remaining EU members, therefore, possible difficulties of enforcement may have an impact on the desirability of London as a litigation forum.
Arbitration with a seat in London should not be affected by an exit from the EU because the UK will remain a party to the New York Convention 1958, along with all the remaining EU Member States.
Overall, although there may be some instability and uncertainty, it seems unlikely that an exit would substantially damage the UK's position as a premier dispute resolution centre.