The Hague Convention on Choice of Court Agreements of 30 June 2005 entered into force in Singapore on 1 October 2016. The Convention applies to choice of court agreements in “civil or commercial matters” (subject to certain exclusions, for example, consumer and employment contracts).
The Hague Convention binds all the countries of the European Union (except Denmark) as well as Mexico and, now, Singapore. The US and Ukraine have also signed the Convention but have not ratified it yet.
Post Brexit, the UK may want to ratify the Convention in its own right (not as part of the EU) to ensure that:
i) Jurisdiction clauses in favour of the English courts would remain effective; and
ii) English judgments would continue to be recognised and enforced in other Convention States.
Please see more detail on the Hague Convention here http://www.pcblitigation.com/media/worldwide-treaty-governing-jurisdiction-and-enforcement-on-the-horizon/